Worst experience at Monster Jeep

I bought a solenoid valve replacement parts at Monster Jeep, the part was not working and had to return for refund. Now, the guys are refusing to refund me and coming up with pretty excuses; first saying if I'm returning the wrong part, and next it's some guy called Louw who is supposed to assist me and he is not available - the last word was Louw will call you back! It's been more than 7 days now and I'm still waiting for Louw to assist me.....