terrible service

i am not happy at all with the service from the department that cancels contracts. most of the agents are rude an d will promise feedback but never happens. i made a call to mtn on the 9th of December 2019 to cancel my sim contract numbers for early termination. the guy who assisted me wa very rude. i had an outstanding balance and paid it together with the amounts he gave me for cancellation. i paid on the 16th of December 2019 having the information in mind that 7days hasnt passed, only to find out when i wanted to confirm cancellation that i was supposed to pay on the 10th of December before invoice date. whos fault is that?? no one gave me information about the invoice date and staff. why should i pay more money to cancel as this is not fair. if i knew i was going to accept the situation b ut now i wont. this is really not fair. MTN for retentions are very rude and they dont care about why you explain to them. now i have to wait for the manager to authorise the cancellation and they are not sure how long this will take and the debit order is going through friday. all of this is really bull **** and unfair. hire people who know their story. this needs to be resolved with immediate effect as i wont take a fall for a rude employee who thinks he knows better.