A tenant may have no legal right to complain, if a landlord is charging "unfair" rent which is well above the amount that a valuer might say is market rent. The lease determines the rent that is charged. In better times a deal may be struck between the landlord and the tenant. Over time circumstances and the economy may change. Rent is not however determined by the rental market at any particular time. Rental is determined only by the lease. But there may be other things which a tenant can do.You may have heard the saying. "A row is never about, what a row is about". In other words when people argue with each other, they often argue about the things which did not cause their initial dissatisfaction. Watch yourself in your next argument with your partner. Does the focus of that argument keep changing? It is the same in law.