Asking a tenant to pay more rent and threatening to disconnect the DEWA

Dear sir/madam,

I signed a contract F with a seller to buy his house. I asked the seller to move into the house prior to signing the transfer document, and he agreed under the condition that I pay him a rent until the date our bank clears his mortgage.

After moving into the house and once his loan was cleared, he sent me an email and asked for more rent and threatened me to cut the DEWA. The transfer should happen next week, what is my legal position?

As per the contract, he is obliged to come to the signature. I told him that if he disconnects the DEWA and asks me to leave the house, then he is breaching our initial rent agreement, based on which I moved to the house.

Can he know use this in court by not coming to the transfer date appointment, saying that I didn't pay him rent?

I confirmed many times that I will still pay the rent we agreed on in the first place unless he cuts the DEWA or ask me to leave.

Please advise!