Eureka Forbes — Not servicing after service Contract

Address:

Mumbai City, Maharashtra

I have entered into service contract with the company Eureka Forbes for servicing of my aqua Gard RO machine on 14/06/11 by this contract they should come for 4 periodical service for my above machine. after many calls they come for 3 service But after so many reminders they are not coming for the 4th service they deny to serve me 4th service. as they says that contract period is for one year and if you give us new contract than only we will serve you. this is 2nd time they are doing this . As I have purchased this machine from them before 2 and half year in 1st duration they also did the same with me and didn't serve the 4th service of the contract.
now this is their practice to do the same and take money of all the services and didn't respond to the complaints I submitted many time.
Please let me know what to do with them.