At present, the deposit money belongs to the tenant.
If the tenant agrees you can have the dposit money, then you can have it. If not, you can either request arbitration via the deposit scheme (the tenant has no obligation to agree) or you can sue the tenant for any provable damages.
Do you have proof of the good condition of all the 'damaged' items at the start of th tenancy? You will only be able to claim for damage beyond 'fair wear and tear' (well you can claim for more but you won't get it )
With regard to the agents responsibility to you, you need to see the agency agreement and work out if they didn't do anything that they agreed to do. However, the ultimate responsibility for any provable damage lies with the tenant.
If you like the information/help provided - Gizza Job
(People under my age won't understand the significance of those last 2 words)