Dell India — complaint about a service centre

I have a dell inspiron 7567 i7 laptop. I used it for approx 2 years. Later it stopped working. It wasn't turning on so i gave to a service centre in thane on 6/4/2019. After two days they gave it to other service centre for repairing which is in mulund. Today it's 31/5/2019 and they haven't done anything. Every time i called them for enquiry they made excuses like they have only one techinician and he is admit in the hospital. I asked them to give their managers contact number but they told me that he is on vacation and he won't be able to talk to you. After this i just asked them to give the laptop back in whatever condition it's in they refused to even do that.
Please look into the matter as soon as possible.