Sending an SMS worldwide is a bit of a challenge as each provider might implement different software and hardware for handling SMS.
We already support a lot of providers in many countries, nevertheless you might run into this problem.
Solution
As a workaround, ask the Support Requestor for an email address and send an email invitation instead of a sms invitation
As we aim to cover as much countries as possible, please send us an email (support@supportsquare.io) describing your issue and mention the country and name of the provider for which the issue occurs.
Don’t forget to Include a screenshot of the SMS containing the weird characters.