I have, as it happens, for a good few years.
There are generally four potential reasons why people don't get paid for work they've done:
1. Incompetence on the part of the employer; this covers failure to prioritise payroll or have a functioning process for invoice payments.
2. Employer has...
Reason 1 is absolutely wild.
You had to insist you get paid on time. That is not being treated decently. Pay, on time, at the amount agreed, is the absolute minimum legal and ethical responsibility any employer owes their employee. No decent employer should come close to not paying you on...