Thank you for your business, we really appreciate it."
"We know you have options, so we really appreciate you chose us to do business with."
"We truly value your business. Thanks for letting us serve you"
"We really enjoy working with you, thanks for being such a great customer"
"Thank you for recommending our company to xyz, your word has a lot of weight and made all the difference in giving us an opportunity to serve xyz as well. We'll make sure we'll live up to your recommendation of us.
"Thank you for sharing your customer experience about our company with others. Your testimonial as a satisfied customer is very important to us, we really appreciate it.