Exorbitant charges on returned router

In the last week, I received two invoices from Webafrica in connection with the refurbished LTE router I returned after cancelling my service - one for R100 for a 1.5m yellow ethernet cable, and another for R50 for replacing the back cover of the router.

The charge for the ethernet cable is exorbitant. A pricelist on comx-computers.co.za gives a retail price of R24 for a similar yellow category 5 cable. Webafrica charged me more than four times the retail price! This is unacceptable profiteering.

The router had no damage when I packed it into the original box and didn't have a loose back cover. How is Webafrica justifying the charge of R50? I have received no communication on why this "replacement" was necessary. If there was any damage to the router, I want to see photographic proof, as well as proof that the router in the photo is in fact the router received from me.