Payment systems locking merchant account

I keep reading over and over about merchants having their account frozen and then having a hard time unlocking their assets. This can drag on for months, sometimes a year with money locked. So why hasn't someone else solved this problem? I won't name any payment companies, there seems to be a few who will freeze an account whenever their is some odd transaction anomaly. It could be a simple spike in sales. It could be when an account goes over some arbitrary monetary level. Is this enforced on the payment companies by the banking institution, or FBI to prevent money laundering, or the Federal Reserve wanting their TAX or just some bullshit to keep the man down? Does anyone have an explanation for why payment gateways act like assholes and get away with this?