This is the most dangerous task to select the broker for you. Most of the traders lose their money because of choosing wrong broker. You can find a reliable broker from many websites that provide broker review. So, be careful when you choose a broker for you.
Well, if you work with a regulated normal broker, then there is a high probability that you just violated some serious rules. And to avoid this, you should definitely study the user agreement in detail. This is important.
Yeah, and if it's not the most honest company, then most likely it's just a blocking to withhold the withdrawal. Of course, you need to be as careful as possible. And check all the information about the company.
Reasons may be different - for example, the use of robots, if they are prohibited. And this needs to be understood. But, in any situation, if you trust the company - you can always communicate with managers and try to solve any issue quietly.