Online care parts

I bought parts from online care parts the part was wrong and I sent it back. They said that the refund will take 15 days. after 20 days i called back and then the excuses started. According to the finance department, the manager has to sign it off and she is waiting for him. It's been almost 3 months now and it's not that big of a sum. I have now spoken to them again and again there are no answers for me. Don't use them!