Poor service

Hi

I bought a battery by you guys for my

BMW x1 2013 MODEL 20i Automatic Sdrive

I have a problem, the battery i bought is not for my car because my car has been malfunctioning ever since I purchased the battery.

I was told that this is the battery for my car and i bought it but I went back to exchange it because it's a problem, I was advised i was sold the wrong battery and I have to add additional money to get the right battery which Is unfair because they had my car info BMW X1 and it is stated on the statement but still they gave the wrong battery.

Kindly assist urgently.im not impressed.