Impression Honda siliguri - My car have problem after service and overhauling

Sir my car have problem last year in july, i visit impression honda service center cooch bihar, but they cant rectify the problem, i paid the service amount and they said visit to impression honda siliguri, then i go to Siliguri, i give my car for further rectification, they start the rectification and complete the work in one month, after i take my car from service center the black smoke comes from the car, but they told me it will automatically cut, after that i go for service again in January this year the problem is same but they cant rectify the problem and told me u drive your car slowely. But the smoke is coming continouesly. I have paid approximately * lakh for the work but my car is not working well please resolve the issue.