Refund for plug-ins that were faulty and support came days and days too late

I have tried getting refunded for some plug-inns that I bought and caused my site to crash and go faulty. The seller took days to get back to me, meaning I missed a deadline and had no support.

Now they are not responding and I have obviously lost confisence in the product and inclusive support.

How do I make a complaint.

Envanto have disabled their contact us link at the bottom of the page so i am stuck.

Envato Market Help and Support