Bad service at core

Me and my wife has made the biggest mistake of getting Marchant device from Momo, at first they promised that we can sell prepaids hence we opted for them. Damn the machine is nothing we are promised, our ****a shop now suffer because we can not offer any prepaid to our customers. Worst case scenario they are busy deducting money from our business account now we on negative but their machine doesn't even have network now. Sies