owner repossession of property

our tenants renovated the house on their own expense and in return we did not increase their rent to cover the cost of their renovation.in addition to this, we allowed them to use our extra lot space for parking and storage. after 5 years, we finally increased the rent and they agreed. the next increase was after another 4 years. at present the rent they are paying is only good for 1 apartment unit but the space they are using is good for 2.we believe that the low rent and minimal increase already covered their expenses when they renovated the house. we requested to correct the amount now to be fair on our part but they refused. we then requested them to leave so we can look for tenants who can pay the fair amount but they refused to tell us when they can leave. we had no choice but gave them 3 months to leave the property even if family members will have to stay for a year, this is for us to legally repossess the property.

does our tenant hold any right over the apartment unit they renovated? we have no written leased contract and the low rent to cover their expenses was only a verbal understanding. my parents own the land. rental law is clear about the grounds for eviction but i couldn't find any about this matter. thanks.