Parcel Post is not the same as First Class Mail. the standard for Parcel Post is 2-9 days, nationwide, on average.With the USPS, only Express Mail has tracking. Delivery Confirmation is available for Parcel Post but that is not a true tracking service.I am curious as to how you know it was shipped on Oct 7th if there is no confirmation service attached.
I believe that is the same as First Class and since you do not know the origin of the shipment you cannot possibly know when you will get it , SO, I would definitely contact the seller!