Thanks - Your suggestions
Thank you for your suggestions on improving our __(product/service/billing/etc.)__. We have already implemented some of your suggestions and I’m sure that you’ll be pleased to know that we have already noticed a marked improvement.
Our __(productivity has increased/billing system is more accurate/service is quicker/etc.)__ as a direct result of implementing some of your suggestions. We really appreciate the time and effort you gave to point out the deficiencies and to offer your insightful ideas for enhancement. Many people will benefit from this, thanks to a great extent to your input.
Once again, thank you for your feedback. It was very valuable and greatly appreciated.