Demand to remove billboard

I am a property owner who entered a 10 year billboard lease with a local billboard operator in Florida 18 years ago. Over the years the operator has attempted to sign a new lease with me, but I have wanted to develop the property and we have operated on a month by month basis for the past 8 years as specified by the original lease. I am now redeveloping the property. I spoke to the operator and advised him of my plans and mailed a certified letter demanding the billboard be removed with a 60 day notice as specified in the lease agreement. It has been 80 days and the operator has not responded.

Can I demo the billboard? What rights does the operator retain? What are my rights to proceed with the redevelopment and not be slowed down by the operator not responding to my requests?

Would appreciate any insignts.