Cant display data on thingspeak properly

Hello guys,

I am sending data from arduino to ThingSpeak from liquid hall-effect based sensor. Normally on serial monitor, data is displayed accurately and variables flowMilliLitres and totalMilliLitres are both unsigned long. However, when I send data to ThingSpeak, the error comes up saying “call of overloaded ‘writeField(long unsigned int&, int, long unsigned int&, const char*&)’ is ambiguous”. When I use int for both variables, the data is sent but at the Channel, it is not displayed accurately. Data is way off how it should be. Arduino code is:

#if defined(ARDUINO_AVR_YUN)
    #include "YunClient.h"
    YunClient client;
  #if defined(USE_WIFI101_SHIELD) || defined(ARDUINO_SAMD_MKR1000) || defined(ARDUINO_ARCH_ESP8266)
    // Use WiFi
    #ifdef ARDUINO_ARCH_ESP8266
      #include <ESP8266WiFi.h>
      #include <SPI.h>
      #include <WiFi101.h>
    char ssid[] = "<>";    //  your network SSID (name) 
    char pass[] = "<>";   // your network password
    int status = WL_IDLE_STATUS;
    WiFiClient  client;
  #elif defined(USE_ETHERNET_SHIELD)
    // Use wired ethernet shield
    #include <SPI.h>
    #include <Ethernet.h>
    byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED};
    EthernetClient client;

byte statusLed    = 13;

byte sensorInterrupt = 0;  // 0 = digital pin 2
byte sensorPin       = 3;

// The hall-effect flow sensor outputs approximately 7.5 pulses per second per
// litre/minute of flow.
float calibrationFactor = 7.0;

volatile byte pulseCount;  

float flowRate;
 float flowMilliLitres;
 unsigned int totalMilliLitres;

unsigned long oldTime;

  **** Visit to sign up for a free account and create
  **** a channel.  The video tutorial 
  **** has more information. You need to change this to your channel, and your write API key
#include "ThingSpeak.h"
unsigned long myChannelNumber = ;
const char * myWriteAPIKey = "";

void setup() {
    #if defined(ARDUINO_ARCH_ESP8266) || defined(USE_WIFI101_SHIELD) || defined(ARDUINO_SAMD_MKR1000)
      WiFi.begin(ssid, pass);

  // Set up the status LED line as an output
  pinMode(statusLed, OUTPUT);
  digitalWrite(statusLed, HIGH);  // We have an active-low LED attached
  pinMode(sensorPin, INPUT);
  digitalWrite(sensorPin, HIGH);

  pulseCount        = 0;
  flowRate          = 0.0;
  flowMilliLitres   = 0;
  totalMilliLitres  = 0;
  oldTime           = 0;

  // The Hall-effect sensor is connected to pin 2 which uses interrupt 0.
  // Configured to trigger on a FALLING state change (transition from HIGH
  // state to LOW state)
  attachInterrupt(sensorInterrupt, pulseCounter, FALLING);

void loop() {
  // read the input on analog pin 0:
   if((millis() - oldTime) > 1000)    // Only process counters once per second
    // Disable the interrupt while calculating flow rate and sending the value to
    // the host
    // Because this loop may not complete in exactly 1 second intervals we calculate
    // the number of milliseconds that have passed since the last execution and use
    // that to scale the output. We also apply the calibrationFactor to scale the output
    // based on the number of pulses per second per units of measure (litres/minute in
    // this case) coming from the sensor.
    flowRate = ((1000.0 / (millis() - oldTime)) * pulseCount) / calibrationFactor;
    // Note the time this processing pass was executed. Note that because we've
    // disabled interrupts the millis() function won't actually be incrementing right
    // at this point, but it will still return the value it was set to just before
    // interrupts went away.
    oldTime = millis();
    // Divide the flow rate in litres/minute by 60 to determine how many litres have
    // passed through the sensor in this 1 second interval, then multiply by 1000 to
    // convert to millilitres.
    flowMilliLitres = (flowRate / 60) * 1000;
    // Add the millilitres passed in this second to the cumulative total
    totalMilliLitres += flowMilliLitres;
    unsigned int frac;
     Serial.print("Flow rate: ");
    Serial.print(int(flowRate));  // Print the integer part of the variable
    Serial.print(".");             // Print the decimal point
    // Determine the fractional part. The 10 multiplier gives us 1 decimal place.
    frac = (flowRate - int(flowRate)) * 10;
    Serial.print(frac, DEC) ;      // Print the fractional part of the variable
    // Print the number of litres flowed in this second
    Serial.print("  Current Liquid Flowing: ");             // Output separator

    // Print the cumulative total of litres flowed since starting
    Serial.print("  Output Liquid Quantity: ");             // Output separator
    pulseCount = 0;
    ThingSpeak.writeField(myChannelNumber, 1, flowRate, myWriteAPIKey);
    ThingSpeak.writeField(myChannelNumber, 2, totalMilliLitres, myWriteAPIKey);
    // Enable the interrupt again now that we've finished sending output
    attachInterrupt(sensorInterrupt, pulseCounter, FALLING); 

  // Write to ThingSpeak. There are up to 8 fields in a channel, allowing you to store up to 8 different
  // pieces of information in a channel.  Here, we write to field 1.
void pulseCounter()
  // Increment the pulse counter

Can anyone please help me with this? Why I cant use unsgined long?

I look forward to hearing from you all soon.

Best Regards