too many problems

We purchased the pro version of this plugin with an addon (event calendar addon) and regretted it. We have had and still have major problems more than a month after purchasing the plugin. The addon doesn’t work at all: in the first phase, activating the addon crashed the site (wordpress was updated and without plugins) and the support fixed it 2 days later. Since then the addon that should save calendar events DOES NOT save calendar events and since then we have no longer had the opportunity to have a solution. We therefore find ourselves with a blocked site, an angry customer and a support service that does not respond and does not resolve. We have opened several tickets, each time they take time but nothing changes. Very disappointed.