Once you come to an understanding of which laws create what privileges then you can figure it out from there.
Turns out you aren't really up against the Postal Service ~ rather you are up against the entire United States banking system ~ and as you've just seen they can tap the Treasury for 2 trillion dollars and nobody bats an eye. USPS is small potatoes in that traffic.
Going beyond that, USPS is simply the federal government agency set up to allow YOU and I access to the letter mail business. Without USPS you have no access since it's otherwise a monopoly of the bankers who have no interest whatsoever in your pitiful small contribution to the stream of letters.
BTW, the federales have this right through the 'post offices and post roads" clause in the Constitution so you'll need to change that too.
Lotsa' luck
A load of rubbish you’ve typed.
Just because the Constitution grants the authority to build roads and maintain a Post Office doesn’t mean that it MUST do those things!
There is no justification for maintaining the USPS. It is losing money as fast as it can, and its labor costs are through the roof compared to private firms. If you think it’s okay for them to lose $12B this FY alone, how much is too much? $20B? $40B? Just how much money do you want to the taxpayers to spend to keep this anachronism going?