I app**** for assistance and was helped very quickly and received constant feedback, but ever since I made the payment to them, all went dead quiet

I app**** for assistance and was helped very quickly and received constant feedback, but ever since I made the payment to them, all went dead quiet. I dont even know whether they are legitimate. Unless I get feedback today, I will see money paid as a life lesson learned and will put this on all social media. Should have received my invoice as proof of payment last week already..... still waiting