Amazon Buy Shipping

Can someone explain to me how it works because seller support is useless and is unable to answer or help. I bought the delivery service via the Amazon Buy Shipping via DPD option, sent the parcel and the parcel got stuck in the depot and there has been no update for several days. I call DPD and get information to contact Amazon because they are the owners of the account, I contact Amazon and get information to contact DPD.