stupid mtn and their lawyers

i paid my mtn account on the 21.01.2018 and closed it and to my surprise the account is still not allocated i get a email from these laywers and i call the at 07:30 this morning and send them the pop and i follow up now at 14:25 and still they havent allo0cate it for they are saying they will do so on sunday *** is with you people it will reflect on my credit report as a default. i swear im going to sue this people if my query is not sorted out by tomorrow 10am