Deregistered my sim card

My phone has been giving me issues due to a faulty battery so it has been off for 2 months now. Today, I sorted it out and put it on so that I could make an important payment only to be told that my sim card registration failed. I tried calling 808 and 173 from a Vodacom number and there is no option to speak to a consultant. I want this issue sorted out and I want guidance ASAP. If I do not make that payment by the end of next week there will be a penalty of 156 POUNDS and MTN will be responsible for that. The confirmation code to finalise my payment will be sent to my cell phone number *** which has been deactivated. PLEASE HELP