What Causes Elevated Levels Of Blood Sugar Despite Taking Medications?

Hi, I m 65 Years old have type 2 dibeties and I quit smokeing 4 months ago, about 2 weeks after I stop smokeing mt blood surgar went to 200, 300 and low 400. I went to my Doctor and the have change my meds three times no results tet I , starting to worry a bit because they put me on insuline and it does nothing. not sure what to do now.