The joy didn’t last long

The plugin worked quite successfully for 8 months, I liked it very much, but then it began to give an error.
I followed the steps to fix it as described here yotuwp[dot]com/faqs/ but the error persists.
Numerous appeals to support for almost a month, through the contact form on the developer’s website, were drowned in a mighty silence. The answer is zero. Sheer disregard. It’s like combing a dead person, in an attempt to revive him.