they broke my key

I left my car for fixing on 4 Jan and the key worked well. Now i am fetching my car and the key is not working. I reported this and was mainly ignored but told about a battery. I am unhappy with this as now I am driving around with the car that cannot lock. This is a huge risk on my side!!! Also to mention I was ignored when I was raising this. Youssouf decided to help another customer instead of addressing my issue.