Being billed still after contract was cancelled months ago!!!

I am super annoyed and ****ed off with CellC. I cancelled my month to month contract with them months ago via email as well as went into stores twice to confirm. I was told it was cancelled and the last amount owed of R70 on the statement was printed out to me after which i made payment and sent them the POP.

I then still received another statement with R229 owed a month later, I them rep**** to them and said this was a cancelled contract and I do not owe them anymore and sent my cancellation as well as POP and statement that was sent before. Only received feedback days later that they sent it to the billing department and will get back to me. 2 new statements later and we are now on R600owed for a CANCELLED CONTRACT, still no feedback from billing and now Ive been handed over! WHAT A LOAD OF BS!!!!