Car Doctor Hari Nagar Delhi

Recently I visited here for minute problem, mechanic here checked and told ecu of steering to be changed, Mr bhupesh drove alone to mayapuri and came back after 3 hrs, (he did not take me with him despite my request) said now ecu (dibbi is changed and car is fine, he charged 4500 rs, I next day found car problem is increased, I asked Mr bhupesh he said it will be replaced on next visit, I visited there on my next week off, he again drove alone to mayapuri and did not allow me to come with, came back after 3 hrs and said dibbi is OK but car has some other problem, I asked him to show the ecu now, I found it was same old ecu of my car for which he charged 4500 rs, I asked him about this he had no words, I felt cheated and looted, also now after he drove for 3 hrs alone to mayapuri I am noticing many other problems in my car which were not present earlier.... How a professional car mechanic (car doctor) could cheat like this and survive.....