How to message that you won't have a CSM going forward

I have a tough one. In the past, we've provided a CSM at no charge to merchants above a certain Annual Contract Value. Going forward, due to a variety of growth-related factors, we are moving that minimum Annual Contract Value up. I wish I were in the position to say everyone would be legacy'd in to keep a CSM if they already had one. That is not the case. How would one message that? Our tech support team is strong and 24/7. They can also purchase a CSM for X. I've thought about including the option to retain a CSM for a discount off of X... 

Grateful for input,
Mary