The answer is yes. Unless the Court ordered you to pay child support and for reason's unbenounced to me revoked your privileges to see your sons.
Not knowing the full story...If their are no court orders that say your visitation with your children have been revoked you should have every right as the mother to see those kids.
If you can, try and do some research on Pro Bono Attorneys who specialize in these particular kinds of cases to help you gain control of your visitations rights.
If there are no other reasons that are holding you back from seeing your sons. Then this should be pursued.