Orders are not being picked by amazon pick up agent

I am new seller to amazon and I have received 5 orders in last 2 months. For each order I packed and scheduled it for pick up but the order got cancelled each time and from the pick up team no body contacted me. I did not even know why my orders are not getting picked up. I raised multiple requests for this issue but there is no resolution yet from amazon side. I have not sold any product yet on amazon because my orders are not being picked by amazon pick up agent.