Usps Refusing Package Drop-off Due To "ship From" Zip Code

I work for a holiday decor company, and we ship a large number of prepaid parcels every day during November and December. Here’s the situation:

- We ship most of our packages from the post office in Town A (where my company is located).
- I live in Town C.
- On my way home, I like to drop off the last batch (about 30 small parcels, each around 5oz and roughly the size of an iPad) at the USPS office in Town B, which is between Town A and Town C.

However, today a USPS employee in Town B told me I couldn’t drop off my packages there because the "ship from" zip code on the prepaid labels is different from their location’s zip code. They asked me to change the return zip code to a Town B zip code so they could get "credit" for the packages.

The issue is: (a) I don’t live in Town B and don’t have an address there, and (b) this seems unreasonable since the post office in Town B is only about 10 minutes away from Town A. I’m not crossing state lines or anything.

We already ship most parcels from Town A, so it’s not like I’m avoiding anything—this is just for convenience at the end of the day.

My questions:

Can USPS refuse to accept prepaid packages like this just because the zip code is different?
What’s the best way to resolve this? Should I file a formal complaint?
Has anyone experienced something similar, and how did you handle it?

They even handed me a printed memo justifying their refusal. I thought USPS was a public service, but now they’re talking about credits and commissions. Any advice would be greatly appreciated!

EXAMPLE = ELECTRONIC POSTAGE...

- ELECTRONIC POSTAGE, packages DROP at other PO locations.

Dear (company name),

It has come to our attention that items mailed by you with Electronic Postage (ePostage, PayPal/Ebay, Stamps,com, etc.) are being dropped off at Post Office(s) in (city where is being dropped off at) and not near your return address on file with your postage provider. You may continue to ship from another location, but the 'Shipped from Zip Code' needs to reflect the Zip Code where items are being mailed from. This can result in confusion for our customers when they attempt to utilize the tracking number to tract the item.

The United States Postal Service currently provides Tracking for all Priority Mail, and most First Class Mail items. Accuracy is imperative to provide service to you as a mailer, as well as our customers receiving orders or shipments. We ask that you remove the 'Shipped From (your Zip Code) Zip Code' selection for your online labels, or input a correct shipped from Zip Code if it is different from your return address.

We appreciate your time in addressing this matter. If you have any questions or concerns, or need assistance in helping us to provide the very best tracking services for you, please contact me at the (your Post Office or contact number).

Thank you,

(name)

(title)

(station)

(public line)