MTN Warehouse delaying process

I ordered a mobile router from Mondo instead I got a home router which I sent back on the 09 March 2023. It is now the 26th April 2023 and each time I phone Mondo as Mtn is debiting my account for something I do not have, I get told that MTN warehouse has not advised Mondo that the parcel has been received. IT HAS BEEN 2 MONTHS. HOW IS IT POSSIBLE THAT MTN WAREHOUSE HAS NOT BEEN ABLE TO LOCATE THE PARCEL SO THAT THEY CAN INFORM MONDO SO THAT THEY CAN IN TURN CANCEL MY ORDER SO THAT MTN CAN STOP DEBITING ME FOR SOMETHING I DON'T HAVE..............