Quickly following up on my email from yesterday. I tried to call you, but was unable to connect. Hoping to set up a call to introduce my company, [ABC Company]. Do you have 10 minutes anytime early next week that would work?
While I have you, I thought you might find some interest in our cooperation with [client name]. We helped them [achieve goal] resulting in [ideally you have a % to use here, but any meaningful result will suffice]. You can read the whole story here: [Provide case study link.]
As a reminder, we're a [Outline the main business] company, expert (or specializing) in the [Describe more spcifically] category. We've worked with [name 2-3 clients] in your country, and help many others to [achieve goal].
I look forward to hearing from you soon.