You question leaves too many unanswered questions to adequately respond. In general, employers cannot withhold paychecks once wages have been earned. If an employer does not pay wages on time, it can be subject to paying a penalty, as well as the attorney's fees you incur in recovering your wage.
Whether you are salaried or not is irrelevant. What matters is if you were an exempt employee or a non-exempt employee. You should either contact an attorney, or the Minnesota Department of Labor to discuss your options.