IndiaMart — charged after discontinuation of service.

Website:

www.indiamart.com

Dear sir/ma'am,

I have taken services of indiamart for leads generation. But i din't get time to work on it so i decided to quit. Thus i send a mail of discontinuation of service. As they said it should be done about a month before, i did exactly same.
I mailed them and they haven't replied on that so i called them after 2-3 days and they still haven't initiated on it. I request them not to deduct service charge for further. But they still deducted a month after.
Now i called them a day before when i come to know that my account is debited, so they called me today and said i haven't received my mail for discontinuation of service and when asked him to check properly he said that mail is in spam. Now it is not my fault but they refuse to refund my money (Rs.2500/-)
Please help!