Hello Jean,
although iv had old as well as new nokia phones the latest being a smart phone ,
iv never text to find the balance of money left in my pay as you go phone, I'm on the asda, pay as you go system , and have always dialled the number instead, to which the balance is spoken instead,
for example It will say to me,.... you have a balance of ££££ ,
so have you got a number to dial instead, its worth looking into,