Refusing to give service from Kent

. I have a RO machine of kent (cost ~ 16000)which is 2 year old.Suddenly it show some problem then i call kent service cnter
“DKPL APPLIANCES

54 MILAN PARK, NEAR SREERAMPUR, GARIA,KOLKATA-84
Telephone : 9804815261
Email : dkplappliances@gmail”
Dated-31/07/2013
They came to our home and change some thing and billed Rs 4500/.
After 1 week the machine show same problem.I called them again they came that day my machine donot show any problem so ur technician didnot do any thing and they ask for service chare i refused to give it because 1 week ago i give them charge for same problem.Again after 1 week my machine totally stop and again i called them they refused to give me service though i agree to give them their service charge.
. Now suggest me what i have to do.
. Thanking you,
. Sarwar Alam
. [email protected]