SMS Extension for opencart 1.5.6.4

Please check the sms extension in this link:- http://www92.zippyshare.com/v/J0k0G4wa/file.html . This extension work with MYSMSMANTRA sms gateway (http://www.mysmsmantra.com). This extension is installed in my online store (Opencart 1.5.6.4). But the main problem is when a customer buy a product the extension display that the sms alert is out but in original no sms alert is out. Please anybody solve this issue. The api details of mysmsmantra is:- http://mysmsmantra.com/api.html