[Plugin: International SMS Subscription Manager] Cannot enter phone number

Hi I setup the plugin. But when I try to type in a number in Malta it will not accept it unless I also type in the country code so e.g. 9934344 needs to be typed in as 5699344344, but the system adds the country code to it so number becomes 3563569944344 so onbviously number does not go through. Shall I edit the code and remove 11 digits to 8 (i.e. Malta code?)

https://www.ads-software.com/extend/plugins/clickatell-sms-subscription-manager/