the loggit variable is probably not visible to the fillLog function. try it with loggit declared as a global variable :
#include <Time.h>
#include <TimeAlarms.h>
#define TMR_LOGGER 60
AlarmId loggit; // create loggit as a global variable
void setup(){
Serial.begin(9600);
loggit = Alarm.timerRepeat(TMR_LOGGER, logTime); // create log scheduler alarm and store the id in loggit
}
void logTime(){
Serial.println("Alarm");
}
void loop(){
}
void fullLog() { // Stop logging when full
addr = 0; // reset address pointer
Alarm.disable(loggit); // shut off logTime alarm
}