Clay Telecom — Frustrating services

I was buying a Chinese sim card from Clay through their website and what a frustrating experience. Super slow website. Loading the documents took me forever and at the last minute I was shown an error page. SO then I requested a call back. A button which wasn’t working on the website. Then I tried chatting with the user on the side. They took all my details and said that someone from their team will call me. Been 3 days, no call yet and no sim card also. I am glad that I experienced their services before hand. I wonder how would their services be post purchasing the sim card.