Renault Kempton bad service

I took my car for service at Renault and Nissan Kempton (ic auto Renault Kempton) on the 17th and was told my sump has some oil leaks which they'll need a new sump..I agreed to it and guess what they ordered a wrong sump and I had to wait another week ,I tried being patient with them then later they told me the chain is slacked and I agreed for chain to be changed after I was told if I don't want to change it if something happens to the engine it'll be on me so I agreed for them to change it,I was told on Monday that I'll get my car Thursday latest and guess what Friday I was told I have to wait till Monday,Monday when I call I was told the person who promised is no longer working there,now when I call they don't pick my calls,the worst service ever, I've been using a taxi for like 3 weeks now, it's raining and winter just arrived ,they do not care about their customers,always have excuses on the delivery day,giving customers wrong quote and overcharging them..I wanted to go home this Easter and guess what I still don't have my car after 3 weeks