The thing with Alt themes is that the developer has made it free of cost, no wonder the payment flow was not working, and therefore it also means that quality and support will be limited to non-existent. Had it been something small I would have addressed it. The only recourse that I see is modifying a copy of the existing default theme to match the Alt theme. Its time consuming so cannot commit a timeline. A workaround of course is to use the default theme in the time being.