Terrible service with no communication!

I went to purchase a new airflow meter which was all good until the part supplied did not work. I went back to the store to let them know this whereby they took the part back and said they will be in contact with a new part +-2 days. 1 month later still nothing. Every attempt at contacting them was net with reading the nessage but not responding. I eventually had enough and went into the offices to get information. They only then told me the part won't work and I have to get an original and will cost ne R600 more. I told them I want a refund because they sold me a part that does not work! They agreed to a refund but then said I have to forfeit 10% for the refund. After some deliberation they agreed to refund the full amount within 4 days. It has been 2 weeks and they still putting it off. Absolutely shocking customer service with bad attitudes and down ride rudeness!