this is in Kansas. Suppose that a tenant T signed a one year lease for an apartment that allows pets under the condition that a deposit/fee would be charged, but the person who put together the lease made a mistake and neglected to include the deposit or the fee despite knowing I would be bringing a pet. The lease was signed by T and the apartment manager, and T, accordingly, hasn't been charged for about 6 months.
However, suppose that T received a letter stating that T was in "violation" of the lease because T had not been paying the fee. Apparently someone in the office realized the mistake and is trying to make amends. But it seems that T would not be in violation of anything in the lease as they're aware that T has had a pet and it clearly states T neither owes a deposit nor a monthly fee.
It is their company's policy to charge a pet deposit/fee, but the lease T and the manager signed clearly states they wouldn't charge T anything. Suppose that it was clearly a mistake on the manager's part, but a lease is a lease. Is T obligated to pay a deposit and this monthly fee, or do the terms of the lease as written override their policy, especially given how much time has already passed?