Bad service

I bought a petrol pump at autozone in Pretoria van der hoff street on the 14th of January only to find out that it was faulty I took it back 2 days later and instead of exchanging or giving me my money back they r taking me from pillar to post saying that it went for testing at their head office but they don't give me feedback it's almost 2 weeks now n m still waiting my car is stuck n I paid R960 for that pump when I make follow ups the manager promises to call me bag but he doesn't. I want a new pump or my money back