Estate Agents Commission

Hi I instructed Estate agent for tenants find service only. They found the tenants but were not very open and honest to disclose information and references of tenants until I signed their terms of business. I signed TOB and asked them to send me their references and also meet the tenants to speed up the process as they wanted to move in so quickly. They sent me tenants referances by email with email saying tenants are arranging for deposit and 1st months rents as we speak. We had not signed the tenancy agreement or nor I had supplied them with EICR at this point. Within one hour of me receiving the refernaces I advised them that I am not happy with the referances and do not want to go ahead with these tenants. Estate agnets is demanding a full fee of £1037 their commision on the basis that "The above fee due, if you wish to pull out of the tenancy." Then they changed to "As outlined in the Terms of Business, our fee is due in full if you choose to withdraw from the proposed tenancy once agreed. Despite your email below advising otherwise, we were given clear authority to proceed with the applicants.The excerpt, below, is from page 23:“If you instruct us to proceed with a proposed Tenancy and subsequently withdraw your instructions you agree, by signing these Terms of Business, to meet the costs and expenses that S J Smith incur, as well as paying the fee agreed upfront.”. Can they demand this. Am I not allowed to decide who I can and can't rent my property. Can someone help please