I don't think so. 35,000 baht is the fee for the agent putting 800K in an account prior to application, then withdrawing the funds after the visa or extension thereof. Part of the money goes to bribing an IO.
If the agent was legitimate, there would be 800K baht in the OP's own account, with a seasoning period. The agent would be charging about 6000 - 7000 baht for the service.
I've known people who have used the non-legit route. So far, they have got away with it. It does not mean they always will.