NO CUSTOMER SERVICE FROM MTN - BEING CHARGED FOR AN IPAD THAT WAS NEVER DELIVERED!!!

MTN is charging me for an iPad i do not have. I ordered an iPad in June 2020 but it couldn't be delivered because they put the iPad number as my contact number instead of my cell number. I tried to sort the problem but MTN could not send me my iPad because it had been returned to the Warehouse. I cancelled the Contract but MTN is still charging me despite numerous calls and a reference number. I get absolutely no customer service. I have asked for a manager to speak to but to no avail. I tried last Friday to contact them again, when I got through they dropped the call. I have tried again today but was left holding for over 20 minutes. I am at my wits end..... can anyone please help me to sort this issue.