Unable to withdraw.

Its been 6 weeks since I requested for a withdrawal from DS Investment but they keep giving different excuses. It actually started in November when I invested 38,000. I made good profit but they kept on encouraging me to make more deposits to increase my margin. At first, I subscribed to it with an additional 10,000 but I began to have some suspicion when they suggested a third deposit without even allowing me withdraw from the initial ones.