Craze Termination Fees charged to Tenants!!!

I am disgusted in Just Letting, they are down right rude and useless. I rented a property from them, when I moved in the place was dirty, full of ****roaches and the carpets were not washed. I complained but to no avail. When it came to renewing our lease I refused to sign the renewal contract and now when I wish to move out, they are holding me liable for all kinds of fees such as Agents commission, paying the rent until a new tenant is found, washing carpets, advertising fees and a cancellation fee. I have sent numerous emails with regards to the fact that we do not intend to renew unless we receive a better rate from the landlord and to date we have still not received any confirmation from him yet I am now held liable for all costs? This is not acceptable and it seems to me that all the agency wants is to make money and they do not care about the well being of the tenants at all. I will never ever rent from them again. So be warned