Shocking service from all at hisense

Shocking shocking service. I bought a new tumble dryer 7 months ago. This tumble dryer stains my clothes with marks that looks like grease or oil. The technician have the cheek to tell me my machine is dirty.. i told him.. how can it be dirty if i put clean clothes from my washing machine into the tumble dryer. I have phone hisense call centre asked that a manager must call me.. no call and 5 days has past. I sit with a new tumble dryer i cannot use as it damages all our clothes. I actually feel like returning this tumble dryer and they must refund me thay i can buy another brand. Shocking service.