Very very poor customer service and refuses to accept responsibility for their mistake

Very very poor customer service. We wanted to port our Business Vodacom number over to MTN as all the other business phones are with MTN business and Vodacom has zero signal in Simon's Town where I live while MTN has full 4G, therefore, making me unable to conduct business telephonically there. There are still 4 months left on the contract, but Vodacom allowed and authorized the port to go through, and only after authorizing told us that we will be charged for the remaining 4 months. I instructed them on email on Monday the 01st June to not port and we will remain with Vodacom until October when the contract ends. Vodacom completely stuffed up and didn't cancel the port and on Friday the 05th of June the phone line was disconnected from Vodacom and ported over to MTN. We spent the day fighting with Vodacom who then eventually said they would port the number back after MTN kindly said they will allow the port back due to there still being 4 months left on the contract. Vodacom point blank refuses to accept they messed up and authorized the port and allowed it to go through after being instructed on email not to. They blamed myself and MTN for the porting issue. Vodacom are 100% at fault here and they offered zero customer service. Very bad for a long standing business client. The correct avenue of action Vodacom should have taken would be to admit their mistake that they allowed/authorized the port to go through and kindly waived the remaining 4 months on the contract and left the port with MTN. Why did Vodacom authorize a port if there are 4 months remaining? By authorizing the port they are actually saying there's nothing owing, yet they said they will charge us. I had no business phone while this mess Vodacom created was sorted and the number was ported back to Vodacom. I have repeatedly asked for upper management to look into this matter and make a fair decision and waive the 4 months as they authorized the port. They just point blank refuse to take responsibility and give customer service. Very disappointed in their lack of service.