Based on the limited facts that you have provided, I suspect that the agency may be able to recover from you the profit it would have made for one year if the contractor's services were provided via the agency rather than directly to you.
One would need to review the agreement and pertinent facts to provide a definitive answer.
This information does not constitute legal advice and does not establish an attorney-client relationship.
In these situations, I would suggest that you go back and review the contract you signed when you hired on the Agency. Contracting agencies contracting out web services is a very common practice. At least in the agreements I have seen from such agencies usually have clauses that prevent clients hiring the contractors directly. They often have a damages clause in there as well. I would look at the agreement, and hire an attorney if you wish to review it for you.
Ripal Patel, Esq.
Your particular situation may be different. This answer is intended for information purposes only. No Attorney-Client relationship has been established.