Sold the land, but retained rights to the cell tower lease

We sold our land, but retained all rights to current cell tower lease, any future extensions or renewals as well. This language was included in the Deed. Landowner signed as part of sale to allow continued easement for cell tower company. Our contract is very old from mid 1990's and only a few paragraphs long it has been bought and sold several times by various cell tower companies, but the original lease is still in place. We have refused each time to change or alter language from original lease. At end of term in 2020 they can renew and/or renegotiate or remove all equipment. Those are only options. Turns out a rep the current cell tower company contacted me and said they paid the current land owner a large amount for perpetual easement. The new land owner knew and signed off as part of sale of land they were never to have any income as part of cell tower lease, but accepted the payment anyhow. The Rep thought his cell tower company messed up and didn't know how that happened with what the Deed states and wondered how that deal got thru their legal review with the new land owner. Now the rep has come back and said they will continue thru current 2020 lease until it expires. It appears they think they can let the current lease expire and not have to renew or do anything with us as current lease holders. The rep will be getting back to us with further information to verify that. Can they continue even if they don't renew or buy us out with only renewal or removal options available in original lease?