Under my name

Hi, I am new to this forum and I hope I got the right forum. I have a question about the deposit (which is made in TDS - Tenancy Deposit Scheme) - a substantial amount is in this service and from what I have read in forums the agency/landlord can not withhold money from the deposit in order to pay outstanding utility bills. However in our contract with the letting agency there is a point stating that the deposit could be well used to pay the outstanding bills. I am not quite sure if they have the right to do this? Aren't utility companies supposed to look for the money owed to them with me personally, not file claims against the landlord/agency for them to pay them off??? I want to dispute the amounts from United Utilities, for example, but I want to receive my deposit back after vacating the property. What would you advise?