Product Images anywhere in Store by Green Tech Online - advertised version compatibility problem

I am a newbie and using the standard version and template with only payment extensions installed OS 3.0.3.1.
I purchased Products anywhere in Store from Green Tech Online through the OpenCart store and when I downloaded the extension (mod) it will not install despite them advertising that it is compatible with version 3.0.3.1
In the modification XML file that comes with the download, I noticed that they are trying to modify among others, Order_Info.tpl ( files with tpl extensions) where this system only has a Order_Info.twig file (files with twig extensions).
This makes me believe that the problem is incompatibility so I have raised a support ticket and asked for a full refund of my purchase or at least some form of support to fix the problem but have to date not received any refund nor have I received any support from the vender (Green Tech Online).
Please can anyone help me or advise me of what I should do

You can ask another developer to provide you commercial support. Me, for example.

Thank you to OpenCart support team.
After they attempted to get support from the developer (Green Tech Online) and getting no response from him, they have kindly refunded me in full.
Thank you all for your support