Contract cancelled without my knowledge

I went to Menlyn store in the middle of January to upgrade my contact and I received an sms which reads as follows : <br> Dear valued customer your case number ***9 has been attended and cancelation has been done. We have cancelled as per your request. Regards Telkom mobile.<br> <br> I phoned customer service and the lady I spoke to told me that I did sent a request to cancel which is not true.<br> <br> I use my data for business use and I request explanation and solution ASAP!