ExSim - I didn't quite explain it correctly.
I, too, use e-mail for a great majority of my business - somehow people "find me" (in a Google search) and then contact me via e-mail for JAA flight tests or FRTOL licences.
Their FIRST e-mail to you would receive a verification request (just like you got when you enrolled on Pprune - and many other sites). Once they acknowledge the service they are never troubled again.
Even better, you can write the verification notice that gets sent to them - so you have the chance to explain.
Send me an 'e' to
[email protected] and you'll see an example.
It really is quite painless.