I tried to do some research and there isn't really too much information regarding them out there on the internet, especially on Sythe. That alone would probably drive me away from using them - it's just too risky. I've also added some links below to sources claiming they're scammers.
It's obviously up to you, but I don't think they have a big enough reputation to be trusted with your cash. You could try and sell them a cheap account/buy a cheap account and see how they go.