REFUSES TO EXCHANGE FAULTY PART

I purchased an alternator from PTA Bakkie breakers in Wonderboom. After installing it the same day, I realised that it was not charging. I then put another alternator on and it worked just fine, so the alternator I bought from PTA Bakkie Breakers was damaged. I called them regarding this matter and they said that they won't exchange it for another one. Other places like Wannenburgs, Freddies Auto Spares, Bemow Spares & City Used spares all give exchange guarantees on such items, so if you buy an electrical part like starters or alternators, they mark the park with a marker and they will exchange it for you, but PTA Bakkie Breakers are not willing to refund or even exchange a faulty part. Even if they don't have another one in stock, at least exchange it for something else if they don't want to refund. The owner told me that my secretary was nasty to his reception and that is why he won't help me. Any excuse. We do understand that it is a second hand part, but really, if this is the way they treat their customers, I will definitely not support them or refer them to anybody every again. R1500 down the drain, just like that. POOR, VERY POOR customer service and customer relations.