Terrible Service

I have app**** online for MTN contract which they delivered the incorrect item on the 08/07 I returned it on the 09/07 to MTN canal walk and emailed Mondo on the 15/07 for feedback on the cancelation. Mondo requested on the 15/07 for a IRMS number which the store supp**** on the 17/07 which I emailed on the day. I mailed again on the 20/07 for feedback with no reply. Emailed again on the 26/07 no reply. Emailed again 02/08 got reply on 04/08 that cancellation was submitted and they waiting on feedback. I email again on 10/08 about cancellation and about the debit order which was deducted end of July of an item which I did not use at all. They rep**** on the 18/08 that a cancellation was sent to MTN. I asked for a reference for the cancellation and date when it was submitted and when I'm getting my refund with no reply as yet. I received my bill for August and again they billing me for a item cancelled more then a month ago for something they sent in error. Please help