You have a lot of experience in customer service but get some testimonials and build up your reputation. Explain to them that by outsourcing to you, they can free the resources of their in-house departments.
Demonstrate return on investment. After the first batch of sessions, there need to be ways of measuring effectiveness.
You should personally conduct surveys from the employees you have trained, and the business should survey their customers. If there has been a tangible improvement, this is a great starting point for you to build up a brand.
Training businesses are always difficult to pitch, which is why your initial research needs to be spot on, as do your diplomacy skills, as you are trying to demonstrate a business’s weak spot.