Indus Towers — agreement over but not discontinuing site

Address:

Kolkata, West Bengal, 700064

We are having a tower at our salt lake residence. Agreement with indus tower has already expired in the month of january 18. From last 1year we have showed disinterest to continue.
But they are not showing any interest to vacate our premises. We have already sent letter through speedpost. Mail is also sent to circle head on 6.3.18 but no action till date has been taken.