Vodafone — Vodafone tower rent

Address:

Solan (H.P.)

Dear Sir/Madam,
I am having a vodafone tower on my house roof top at Solan (H.P) for nearly last 15 years. For the last 2 years vodafone hasn't paid me the tower rent in my account which they agreed to pay at the time of contract. Despite making numerous calls to them, the issue hasn't been resolved and neither they are taking off the tower from my house.
Please suggest a most suitable method to resolve the issue ASAP.