My landlord treated me unfairly / the property was in an unacceptable condition, what should I do?

The Zero Deposit Guarantee is an insurance product to protect your landlord from financial loss. Unfortunately, therefore, we can only consider a claim from the landlord, not a counter-claim from you about the property. 

If you believe your landlord has breached the tenancy agreement, then you will need to take up any counterclaim directly with them. If they are not willing to engage, then you can pursue them as you would for breach of any other contract.