Agent's fees

[hmmmm]

I signed a 12 month AST in October last year. I told the agent that I may be willing to move into the property myself after 6 months and whether I should do a 6 month contract instead.
I was told i can do a 12 month contract with a 6 month break clause. I gave the tenant 2 months notice in January so that they could go after the 6 month.

When I signed the 12 month contract I was told I would get 6 months worth of commission back if the tenant left after 6 months.
Now they are saying I am not entitled to it.
Is this common practice?!!
Also, the tenant handed in the key one month early after finding another property. I will not be getting my final months rent as apparently i told the tenant to leave!
Am I entitled to chase the agent for this rent.
I have not signed anything to say the tenant can leave early, but did indicate to him that if he did find somewhere else before the 6 months is up, we could come to an agreement if enought notice was given to me.

[mind the gap]

You are only entitled to it if you can prove that it is what you agreed to in the first place in your contract with your agent. Read the Terms and Conditions. If it is not made clear in writing, then you will struggle to prove you were promised a refund if the T left after 6 months.