I am from Singapore. This is our first time selling our first hdb flat. For selling of our hdb flat, we called this agent from his advertisement. He came down to our home & on that day he asked us to fill the form to submit to his agency if we want him to sell our flat for us. He told us that in order to do marketing for us officially, we have to appoint him as our agent. He didn’t mention as sole agent. We just signed & we didn’t know that it was a 3mth exclusive contract till we met another agent through recommendation from our friend.
2nd agent told us that the first agent is entitled for commission whoever sell our flat. I was very angry to know that. He didn’t mention about it before we signed on it. He said it was a form to submit to his agency. If we knew the full meaning then we would never sign on such a contract. We want to pay commission to who sell for us. Otherwise I feel it is not fair to us to pay him commission if we sell ourselves. Please advice us how we can cancel it. 2nd agent told me that no way to cancel it. We have to wait for 3mth to terminate it. 
Is that true? But he paid for us for valuation & resale application fee. So far we pay nothing to him yet. Beside this contract to lock us down, this agent is ok to us.
There is no way to cancel the contract but you can take the house off of the market for the remaining portion of the agreement. If the house is eventually sold to anyone that the first agent showed the property to, you will still have to pay him a commission even after the 3 month contract runs out.