Airtime contract night mare

I had a airtime contract and has been changed to a prepaid as I have finished the contract with them. The problem is I have lost my cellphone and I am unable to do sim swap as the account is still under RMCS and at Vodacom they are asking for a confirmation letter from RMCS to confirm that they can do the SIM swap. what is frustrating is that customer service from RMCS are not helping at all, as they only confirm that the account is on prepaid and they can not write the letter. This is frustrating as I use this sim card for my business and everything is on stand still guys . RMCS is not helping at all. I am so frustrated I need HELP urgently !!!