Inconsistencies in refund policy. Double standards.

So my husband went to Sparksport in raisethorpe on Thursday, he explained that I have a mosquito bite that got infected by scratching. They gave him a cream which is R110.00. When he got home I told him I have this same cream. The next day I took it back to Sparksport and explained that I already have a full tube I would like refund or another product (because the cream didn't help). To which I was told because of the antibiotics in the cream and the temperature variations they are unable to return the medication. So the question arises, you have a controlled temp in the pharmacy? How is the cream effective because there is a temp change as soon as I leave the store. Because I've left the controlled temp within the pharmacy and stepped outside causing a temp change means the cream and antibiotics in the cream are ineffective.... This is essentially what you are saying if you are using this as the reason why you can't refund me my money.