Need to modify an extension for opencart

Avg Bid (USD)
Project Budget (USD)
$30 - $60

Project Description:
I have an extension for send SMS to customer.

It is work very well,The problem is that it is not support Arabic characters.
When I send SMS contain "????" it send it like this"????" ,so it replace all chars with question mark.

This is the extension link [url removed, login to view];extension_id=9128&filter_search=sms&filter_download_id=29

Skills required:
eCommerce, MySQL, Open Cart, PHP
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