refusal to accept returned item with a reciept

on the 03/10/2015 17:14 I purchased a tablet cover and when I arrived at home it was not a bigger than my tablet, the following day 4/10/2015 I went back with my receipt they didn't have a right size and Michelle Williams the supervisor said it a company policy no refunds and she was very rude. she said its from management I then called the manager Ms Colleen Wilson who also send me an email confirming that it is indeed so. please help me because I don't think this is legally correct and I wasted fuel and time about 25kilomotres drive. if feel that Vodacom's policy is so unfair . please help