Is SEEFF Properties reliable?

SEEFF Properties promised that the sale of my apartment will be finalized within a period of 3 months. However, SEEFF failed to put an expiry date in the OTP by which the purchaser should have finance by. Therefore, it is open ended and works in the purchaser's favor. Unfortunately, I trusted SEEFF and gave them a sole mandate to sell the property. It has been 6 months since the purchaser has signed the contract and I still have not received the full payment for the property.