Bad customer service

I bought a starter for my Proton Gen 2 3 weeks ago; the car is standing in Potchefstroom, and I only get to the place yesterday. When I took of starter i saw it was the wrong starter, they supp**** to me. They told me it's the correct one. Now that i want to change it the person wants to charge me an extra 50%. People please don't support these people. They are not good people, and they will try to make money of you even when they were at fault. The most annoying thing is they never tell you it's a 3-day exchange period.