MTN Airtime disappear - Customer care have different reasons.

I have a MTN 100 Topup contract with MTN. With this contract I receive 25 sms's and R110 airtime per month. We do not use a lot of airtime on this phone for my dad mostly use Whatsapp(via Wifi) and incoming calls on the cell.

This means that the airtime will accumulate for the 6 months to roughly R600+. This has been the case now for the past year. On the 1st of March 2018 we checked the airtime via USSD and it was roughly R600. when we checked on the 2nd of March 2018 it was down to R169. I visited the MTN store in Centurion on 5 March 2018 and they informed me that it was data that was used and I had to contact 1555 from the phone and they will show me what happened. I contacted 1555 this morning (6 March 2018) and there was R216 airtime left. They now informed me that it was airtime that expired after 6 months. This is now confusing.

I tried to explain to the consultant (who was very rude) that airtime expire after 6 month will mean that if the airtime is loaded beginning of December 2017 and it expires after 6 months it should be available till end of May 2018 if not used. The consultant infomed me that the R216 airtime on the contract is January and Feb airtime and all airtime from July 2017 to December 2017 has expired.

Firstly the airtime shown by USSD differs every day and actually becomes more than the previous day. secondly how can Airtime be valid for 6 months and then expire after 2 months. This is a loss to myself of more than R400 in airtime.

I have Cell contracts with other(not naming) providers and their airtime do not expire/disappear like MTN

Queries can be send to cell number listed and not the contract number