Are your customers located in the same area where your production is located? It's easy to sign a non-compete and/or do not compete clause as part of the contract. But really if you get right down to it, you keep him busy with work and you are fulfilling your clients orders, why would he/she 'cut their own throat' and try and eliminate you. You will have to make sure you focus on customer service and if a customer has a question it must be your company that takes the call. Just my two cents.