Hello
Just tried the import, it works!!!
I was unable to map the products since they are different from what I had on WHMCS and the new ones for Blesta, at the end of the import there was some error but when I checked all clients are imported with phone numbers and addresses, so that's great!
Don't forget to allow MySQL connection to connect from the new (blesta) host to the old one (whmcs), also, you will need to make sure that there are not users matching at both sides, the import didn't want to overwrite users from WHMCS to Blesta, so I had to rename the email field on Blesta side....beside that everything works fine.
Thanks a lot!