Poor Service

I booked fir minor service and battery replacement. The mechanic came with a wrong battery. The minor service was done. He went back with the battery and after a 2 days I was told that the right battery was ready. The mechanic came and fitted it in. After a week, the battery warning light is back. I took the car to Mercedez benz and it turns out that the battery fitted in is still not the right one. A 652 was fitted in instead of a 658 - AGM. I have requested them to come and take the battery back for a refund. I am waiting for feedback. I chose them for convenience but has ended up being inconvinienced.