My employer does follow overtime regulation, what should I do? am owed more $4000.00

While your factual situation seems to violate the law, your question doesn't have all the information in it necessary for a definitive answer.  In general, an employer owes overtime at 1.5 times the hourly rate for all hours over 40 in a given week.  There are however arrangments permitted under the law for irregular workweeks with guaranteed rates of pay. Did your employer enter into any type of written agreement with you regarding your hours and pay? If this issue is one that just affects you or you and a couple of people, the most economical route would be to visit the local office of the US Department of Labor, Wage & Hour Division and file a complaint for unpaid overtime.  There is an office in every major city in Texas.  The DFW office is in Arlington. If your employer is treating numerous past and present employees in the company in this manner, you may want to seek out the advice of an experienced labor & employment lawyer (look for someone Board Certified in Labor & Employment Law www.tbls.org) to discuss the filing of a collective action (something of a class action on behalf of all similar employees).