A. In the absence of Rent Agreement, you need to issue a legal notice by mentioning all the details i.e, rent, deposit, arrears of rent, eviction clause and rent commencement date etc., by doing so, it will establish what are the terms of the oral contract is exist unless denied from the tenant in reply notice.
B. Thereafter, you can file an eviction suit before the Court if the tenant fail to response your notice properly. For your information, you don't enter the premises unless obtain tenant consent.