Cell C - incorrect account charge

I have submit a contract cancelation notification to Cell C in April 2019 for cell nr ********** 383. We received an sms notification on the eve of the 7th May the contract expires. We then recharge the number with a 200 gig data package and airtime. A few days later we received an sms notification that my account will be deducted at the end of May with the ammount of R1700 round about. The contract ammount was R1155. On the 13th May I queried this as the contract did expired on the 7th May and we moved over to prepaid. We did submit the cancelation notice to Cell C within the time we were told to do so. On the 13th after talking to numerous people and being transferred to several departments I was talking to a person in the contract department explaining my issue. At firts I was told that I am being billed for April's account. I told the person that I disagree as the 30th April they deducted and ammount of R1155. 96 this was for April account. They should only deduct at the end of May the 7 day pro-rata use of the contract. The lady told me that we received the full month package usage and I told her that was terminated on the eve of the 7th. We did not had any usage of the package after that time and had to recharge the phone. I received case nr. ********** 917 after requesting it to be sms to me in order to have proof. I was told I will get feedback within 24 hours or 48 hours. Which I didn't get. I called back on the 21st May and had spoken to an Ayanda at 1:05PM. I explained the whole issue again and she actually saw the mistake accounts had made and submitted a query to accounts to fix and resend the invoice. With reference nr. ********** ********** telefonically. A few minutes I received an sms with a new reference nr ********** 467 stating they have received my query and will attend to it shortly. I will receive an sms when query has been resolved. I received no feedback up until today yet. This morning I contacted Cell C and spoke to a Molekele and was informed that he is putting me through to the legal department. I hang on from 10:30 until 11:00AM this morning. No one answered.

I did told them on the 21st that they should fix this issue as I will not allow this amount to be deducted from my account.

I dont get positive feedback and it seems Cell C is reluctant to solve the problem. Hopefully you are able to assist me with this matter.