I think it's hard to say in exact numbers. This thread was started on March 28th, but I doubt they had any real clients right from the beginning, unless they were promoting their service through other channels. So, I presume most of the transactions during that period involved their own funds. As of the start of April, the address had accumulated a total of around 3BTC.

https://bitinfocharts.com/bitcoin/address/bc1qf8h5k6sash8007vpesymxkw2xsg5d0r3j4l5vmcrwpz2pqu66fjstzgd3r