Please note these are all suggestions, and should not be considered "the rule". As stated, contact an attorney! While discussing your options with an attorney, go to the Garvin County courthouse and research the deed/title, as recorded with the county, (assuming you are referencing Maysville and Garvin County as submitted on your question). Verify ownership prior to any legal actions. Don't spin your wheels if you have no legal right to do such.
Based upon my limited experience with "eviction proceedings" in Oklahoma, an occupant has to be removed with civil court proceedings, notification, and county enforcement. Also, tenants have rights, regardless of any monetary agreement or signed/unsigned lease. You can research "the rights" more by searching the Oklahoma Landlord Tenant Act.
Best of luck!