Not multilingual / not secured / a lot of bugs

This plugin could have been nice but :

– It says multilingual support : You can translate a few sentences in the admin panel but the majority of labels are directly in the php code. The .po file seems to be useless because I never manage to display one of my tranlations from this file.

– The source code is just bad developped… a lot of duplicate code, no optimisations, no good practice. You can easily apply for more points than you really have.

– 2 customers used their points before I removed the plugin : The first used more points than he really had. The second still had the points he used after his purchase and get the points for the new purchase… so in time he should have more and more points…

– In top of that, the plugin authors refused to refund me because I didn’t let them access to my backoffice and FTP to correct the problems. But I can’t trust them, and if they introduce any other bug I could have lost money… (a better idea is for you to test your work properly / bugs can happen, but this is too much and too critical).
I bought the plugin because it says it has multilingual support which is a lie, for me it is a good enough reason to ask for a refund !