UPS Ground saver delivered to a business that used to be a post office (old USPS address).

So UPS delivered to what used to be a post office but is no longer a post office - it's a private business. Logically, USPS says they didnt receive it. UPS is acknowledging that is the issue, but says there's nothing they can do or claim that can be processed. We delivered to the wrong place, but no way to fix the mistake. I understand the level of service is slower with UPS Ground saver, but is it really FU we can just deliver your package to a dead end and wash our hands of it?