Midas Komatipoort

Earlier this year i ordered a cv joint for my car at midas Komatipoort and received it i gave it to my mechanic but he took 15 days to fit it. When he tried to fit it she see its the wrong one. I took it back to midas for a refund but the said its older than 10 days. Last week i ordered n second one from midas and told the guy "ben" at midas to make sure its the right one, i received on Thursday and friday took it to my mechanic. He took out the old one and prepared the new one by fitting it he see its to smaller on the cublinks. I took it back to midas to ask them for my money back. They refuced to refund me because the plastic bag is broken and we already put the grease in. Why must i suffer twice the payment and labour out of my pocket, if they order the wrong one. You can not see its different before u want to fit it. Please help me. Barend viljoen ***