Cenvat credit of service tax

We are recently started a budgeted hotel industry and we got a online portal bookings for room reservation. Online portal companies are collected amount from guests, But online portal companies are deposited the amount to our bank what we committed with them. For example our rack rate is 2050/- inclusive of all taxes, they deposited 1650/- inclusive of all taxes. We raise the invoice on the amount of Rs.1650/- on the portal company and the rest of balance amount we can show a discount. We cannot deduct any TDS , because online company has deposited the amount of Rs.1650/-. The online company has showed the balance amount as commission and they sent commission invoice , inthat they mentioned service tax details. Can we avail the service input....... and one more is we cannot book the commission. How can we avail the service input. I want to know the clarification on my Query ? 1. If TDS applicable.... How can we deduct the TDS( we are not repay the any amount to them) 2. If service input can be avail....... How can we avail (we are not mentioned as commission in our books/ invoice)