Debited for 3 months instead of one

My name is Sindisiwe Masinga and ported my number from MTN to FNB connect for business purposes. I have only been with them for just 2 months and they decided to debit 3 months instalments instead of one. When I called on Friday 1st Sept to cancel my account as well as ask for my money I was told to wait 72hrs. On Monday 4th Sept Lesekgo called me explained they acknowledge it's technical error and promised my money will be debited on Tuesday 5th Sept and I was okay and decided to continue with their services. On Monday the bank charged me for a debit that did not go through because my account was in excess. Today I have phoned 4 consultants who all promised to escalate the matter and promised someone will get back to me. Consultants I spoke to were Boitumelo , Gugulethu , Katlego and Lebo. No one bothered to call me from the relevant department and consultants were not allowed to transfer my call. Only after I started screaming and shouting with frustration and told one consultant that I am going to Hello Peter did I get another call from Lesekgo who tried to explain there is delay and I the matter will be sorted on Friday. I lost it again and have told them that I need to port my number back to MTN because this is my business number since I have 1000 cards printed and all website ads have this number. This is unacceptable and has created issues on my account which they won't pay. This means my account will be in excess for 4 more days. And when that money comes in an additional amount will also be deducted for unpaid debits. I will really not. advise anyone to port their number.