Worst Network providers

My number was ported over from CELL C to MTN without my knowledge on Sunday. I managed to get it reversed on Monday. I got my number and I use it to create contracts but the same night these people who had my number moved to MTN were still able to create contracts under my login though I had reversed the port and let CELL C aware of what's going on with my number. I really don't understand what's going now? Weren't the people who had my number on MTN suppose to lose network the moment I got it back, if so how were they still able to create those? I'm really running out patience with Cell C as so has my colleagues because they did it to her twice already and she was Cell C. I don't know what these networks want us to do to show the seriousness of this situation. We dealing with ***** and we've let you aware and you still letting it happen!!!!