I’d reposition the first line to be about the customer rather than what you do. Why would they care?
Then I’d focus on removing as much of the extra text as possible. Anything that doesn’t need to be there/things you wouldn’t say in person should get removed.
For example –
This led us to uncover that most of them were greatly over overpaying for a service they were not happy with, or wasted time and energy trying to do it all themselves.
“We uncovered that they were overpaying, weren’t happy and wasted time trying to manage it themselves.”
Other than that, it’s pretty compelling. I’d do a softer follow up email though as only a certain percentage of people will want to jump on a call.
The next email could ask if they want you to calculate their savings, they say yes, then you ask them to jump on a 5 minute call to get the data to do the calculation.