Mobile Phone Credit gone !

[in a mo]

I checked my credit balance a couple of days ago Total £7.00,when yesterday I tried to send a text all of the credit was gone ,I am the only one who uses this phone,what could have happened,any ideas la

[sunny-dave]

Sometimes credit is only valid for 30 (or 60 or 90) days from the time it is purchased?

[friedgreentomato]

have you received any 'junk text' that sometimes wipes out your credit

[dotty.]

do you have any bolt ons that may have used the credit balance?

[AB Editor]

Been online with it by accident?

[cazzz1975]

is it a new sim?

[murraymints]

have you unwittingly subscribed to something via an on line comp...small print usually says this will cost £5 per week...is on the ipad iphone comps that keep popping up !

[in a mo]

Thank you all I have quite an old phone really it is basic ,I did not know but it does have an internet connection ,this has now been disconnected as I do not need IT,very pleased to say the amount that had disappeared has been put back on .well done Vodafone

[deggers316]

Jesus arn't you lucky ??

[in a mo]

I had to work hard ,but I truthfully did not know that my phone was GS3 I could not believe it ,I did most of the work on chat the result of that was oh never mind, you did not have any money on that account ,have a nice day what is left of it ,you will have to speak to another department, this was said on 2 separate occasions ,the 2nd time was ,you need to speak to Pay as You Go Dept,I am part of customer services,so it went on, it was then my mobile rang ,it was PAYG,the guy read the notes ,had a word with his manager and within seconds money back on the phone .
Oh BTW Well done AB Editor great Answer.
Thank you to all I was really grateful for all of your answers.
IN A MO