Here are a bunch of Paces (see pacing and leading) that you can use for customer service emails or calls:
- I know/understand) how important this is to your business / this is important to your business
- (I know) you want to fix this quickly
- (I know) this affects your business
- You would like to ….
- We have dealt with this before (you and I)
- You can’t please everybody all the time

Pacing and leading is a fundamental element in rapport. More on business writing here.