We utterly dispute our return being non refundable. Total lies!

My husband and I ordered a Defy oven. When it arrived we carefully cut the top of the plastic wrapping, removed the side polystyrene sides and immediately realized the oven was too small (we have an oven installed already and needed a new one). My husband measured it and it was in fact far too small. We re packaged it, with the exact plastic wrapping and polystyrene as received and logged a return. We've been told that we sent the product back defective and they won't accept it. How is this possible when we never fitted it, or anything!!!! We absolutely refute this. Now nobody wants to help us and they returning it to us! We did nothing to the oven, we didn't install it, use it or anything. Only unpacked it, measured it and repacked it. This is unacceptable! We are very upset with this shocking service. We emailed our dispute only to get the exact response back (looks like a copy and paste reply).... We do not recommend buying anything of high value or large appliances from Takealot.