Bad service and incorrect billing

I was with Nashua Mobile and had the changeover done in October when Nashua closed. At the same time I had an upgrade to MTN Sky package. However I had a Broadband 300mb and a 1GB recurring data packages on my previous contract. I am still been billed for them even although I am on Sky mwhich has free data. I have phoned in numerous times sometimes for upto an hour and never an answer. I have been to Vaal Mall MTN twice and they have Mtn Active refno *** / USD *** and still nothing. My account keeps getting locked cause I don't want to pay it. I just keep getting told if I don't pay it they won't switch on my line so I have to keep paying it. Again yesterday morning I was locked because I didn't pay the data. I then paid it and MTN collections recieved it at 13:43. I spent 53 minutes on hold yesterday and to be disconnected. At 19:43 I received an sms to say they received proof of payment. Till now I can't get through and I am softlocked. I am fedup with this service. I am sorry Nashua Mobile had to close cause always had good service by them and now I have to deal direct with MTN. I also want to be refunded all the data I am paying for which doesn't get used.