Not Collecting Cancelled Order

Hi, I've engaged in a contract with Vodacom on the 13 September 2018 but cancelled the order before it was delivered. I was told that the product was already in process to being delivered. Upon delivery I decided to to take the laptop but to my disappointment the computer was faulty, and I immediately contacted Vodacom the day after to cancel again. I have since then phoned several times but every time I'm being told the same story, "the courier tried to contact you but no answer", and they would check the contact number and the number is not mine. I've been a Vodacom client for approximately 10 years and they don't have my contact details?, how convenient. All I'm asking is that they collect the laptop because I'm being charged for something I'm not even using or want, or are they intentionally ignoring me? Furthermore when they had to deliver the laptop it was no problem.