Now I have received the following response in the site's chat:
Your transaction is being processed by the system. The timing of transaction processing depends on many factors in the operation of the blockchain network and payment system of platform. Sometimes the time for withdrawal processing can be several minutes, sometimes - several hours, day or more. You don’t have to worry. Please, wait for the completion of the transaction processing.
Here is an online screenshot -
http://joxi.ru/DrlzDOKC0QL8Q2It was interesting to find out that bitcoin transactions take a day. We'll see..
If this were true then it would be a big problem for a gambling site, everyone knows that credibility is the most important for a gambling platform.
I will wait for the way BETMATCH.IO handles such cases, if everything is fine I can join and try it out.