Consumer Redressal

this is to inform you that I have a problem with the hp service center located in cit road Kolkata I had taken my hp printer to the service center and they have charged me Rs 900 and I paid the amount and bought the printer home when I checked it in the house it had the same problem and I could nt use it .I went back to the service center and told them that its nt working and have the same problem .they gave me the job sheet and told me to come after 7 days and then when I went to them after 7 days they tells me to pay Rs 3500 more to solve the problem where else the total cost of the printer is Rs 5500 for a new one .I have been fighting with them on online and going there and trying to tell them to help me but they everytime tells me to take the printer back or shell the amount which is 80 % of the price of the new printer .please help me because CONSUMER FORUM is the last hope .I have all valid documents against them awaiting for your reply eagerly thanking you