Takealot sent me a locked computer and now refuse to refund me 30 days after the return

Takealot sent me a ‘new’ Macbook Air in April. When I opened it, the Apple box was already opened, the computer was dirty and it already had an account that belonged to someone else. I immediately logged a return, stated the problem and asked for a full refund. It’s been more than 30 days, countless emails and telephones calls to Takealot and no answer or update from Takealot. They emailed me 2 days ago to say they refuse the return and will be sending me the same computer again. This is not only pathetic service, but *******.