Terrible service

I bought a battery for my Mazda CX 5 before i took my car for service, was told that the istop light will switch off after fitting the battery. The light did not go off. I then took my car for service and was told that the battery that i fitted was not the right battery as i had to buy duratech battery. I went back to then ad was told that Mazda is not telling me the truth and was told that one of their suppliers will call me, he did call me but the call did not yield any results as he told me samething that they told me, They then requested that i give them the numbers of Mazda and i found that surprising because it is on the invoice that i gave to them, i went back to them and was told that the manager will call me, to date he has not called me. I am now stuck because battery clinic and Mazda are giving two different stories and i dont know who to believe. I even. Offered to pay more so that i can get the right battery and was told that they will get it from one of thier stores. When i called for the second time i was told that they dont have duratech battery, i am so disappointed with their service