We've been having issues with Stamps.com labels purchased through Shipstation.
I am not sure if it is intentionally Shipstation shows lower rates for Stamps.com and then, after the label is purchased, you get an adjusted bill.
We lost shipment and filed a claim through Shipstation. UPS approved the claim.
Stamps.com does have any idea about it. However, it's been more than three months since they are not refunding us the label cost, which is $160. I received a reply from firstname.lastname@example.org that I should've filed a different claim through Stamps.com.
Reaching Stamps.com and Shipstation support is not easy.
Even after I contacted Shipstation, tickets are staying unanswered for weeks.
I hope Shipstation will find a way to display the actual rates from Stamps.com.
We stopped buying any labels from Stamps.com (UPS and USPS) through Shipstation and using our own UPS account even if it is slightly higher. At least I know we can reach the UPS team, and they can handle our claims faster and better.