Receiving numberic input and storing in EEPROM

Hello, I'm working on this project where I need to send a text message to a phone number.
I don't want to hard-code the number into the program but for the user to be able to type it in using a keypad and it would be stored in a character array that is then used by the program.

When I try to implement this, I observe that only one digit is stored in the eeprom.
I'm checking this by printing it out.

I have sectioned out the part of the code doing this alone and included here.

#include <LiquidCrystal.h>
#include <Keypad.h>
//#include <SoftwareSerial.h>
#include <EEPROM.h>
//SoftwareSerial mySerial(11, 10); //Rx and Tx respectively

const int buzzer = 12;
int led = 13;
int smokesensor = A0;

char phone[15] = {};


//LCD Config
const int rs = A2, en = A3, d4 = A4, d5 = A5, d6 = 1, d7 = 0;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

//Keypad config
const byte numRows = 4;         //number of rows on the keypad
const byte numCols = 4;         //number of columns on the keypad

//Keypad map
char keymap[numRows][numCols] =
{
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

byte rowPins[numRows] = {2, 3, 4, 5}; //Rows 0 to 3 //if you modify your pins you should modify this too
byte colPins[numCols] = {6, 7, 8, 9}; //Columns 0 to 3

Keypad myKeypad = Keypad(makeKeymap(keymap), rowPins, colPins, numRows, numCols);
char keypressed;

char phoneno[14] = {};

void setup()
{
  Serial.begin(9600);
  pinMode(13, OUTPUT);//set buzzer to output
  buzzercall2();
  lcd.begin(16, 2); //initialize the LCD
  lcd.clear();//clear the lcd screen

  //this loop aims to load the contents of the eeprom addresses into the char array "phoneno"
  for (int xxp = 0, xyp = 10; xxp < 15; xxp++) {
    phoneno[xxp] = EEPROM.read(xyp);
    xxp++;
    xyp++;
  }
  lcd.print(phoneno);
  Serial.println(phoneno);
  delay(2000);
  lcd.clear();
}


void loop()
{
  keypressed = myKeypad.getKey();

  if (keypressed == 'B') {
    buzzercall2();
    changenumber();
  }

  if (keypressed == '#') {//to display the number
    lcd.clear();
    buzzercall2();
    
    lcd.print(phone);
    delay(3000);
    lcd.clear();
  }
}

void changenumber() {

  //char plus_sign = '+';
  int char_no = 0;//char_no is used to point to the character in "phone" char array
  int lcdrow = 0;
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Enter Phone no:");

  while (keypressed != 'A') {
    keypressed = myKeypad.getKey();

    if (keypressed != NO_KEY && keypressed >= '0' && keypressed <= '9') {

      lcd.setCursor(lcdrow, 1);
      lcd.print(keypressed);

      phone[char_no] = keypressed;

      buzzercall();
      char_no++;
      lcdrow++;
    }
  }
  buzzercall2();

  int xyp = 10;//xyp is used to set the address of the eeprom to be written to
  
  for (int xxp = 0; xxp < 14; xxp++) {//xxp is used both for the for loop 
    //iteration and for the character in the char array "phone" pointed to
    EEPROM.put(xyp, phone[xxp]);
    xxp++;
    xyp++;
  }

  xyp = 10;//xyp which has been declared before is used
  for (int xxp = 0; xxp < 14; xxp++) {
    phoneno[xxp] = EEPROM.read(xyp);
    xxp++;
    xyp++;
  }

  Serial.println(phoneno);
}


void buzzercall2 () {
  for (int i = 0; i < 2; i++) {
    digitalWrite(buzzer, HIGH);
    delay(70);
    digitalWrite(buzzer, LOW);
    delay(15);
  }
}

void buzzercall() {
  digitalWrite(buzzer, HIGH);
  delay(150);
  digitalWrite(buzzer, LOW);
}
  for (int xxp = 0; xxp < 14; xxp++)  //xxp is used both for the for loop
  {
    //iteration and for the character in the char array "phone" pointed to
    EEPROM.put(xyp, phone[xxp]);
    xxp++;
    xyp++;
  }

Why are you writing each character of the phone array when you could write the whole array using a single call to the put() function if it was zero terminated to turn it into a C style string (NOT a String)
Why are you incrementing the for loop variable inside the for loop ?

isn't xxp being incremented twice?