In your case, because one party has not signed a contract, it is deemed that the lease contract relationship has not been established in writing, then you are deemed to have established an indefinite lease contract relationship.
According to the relevant provisions of the Contract Law, if the lessee fails to pay or delays the payment of rent without justifiable reasons, the lessor may require the lessee to pay within a reasonable period of time. If the lessee fails to pay within the time limit, the lessor may terminate the contract.
In your present situation, you can do this,
1. Urge the lessee to pay the rent owed within a certain period by SMS.
2. If the notice period expires and the lessee still fails to perform the obligation of paying the rent, he may terminate the contract and bring a lawsuit to the court. It doesn't matter if others can't find it. When the court serves a summons, it will serve the parties in the form of an announcement that the defendant has escaped or disappeared; In addition, according to the relevant reply of the Supreme Court, the court that brought the lawsuit may bring a lawsuit to the court involved in the leased house. )
You should take good care of what he left behind. When you bring a lawsuit to the court, you can ask the court to give you the right to be compensated in advance by selling or auctioning if the defendant refuses to perform the plaintiff's rent according to law.