Mind if I chime in here OP ? OK Thanks:)
First off let me just say I don't proclaim to be as astute or skilled a businessman as you or some of the others are here But I do pride my self on having a bit of common sense.
Now , One thing I am pretty sure of is one off the essential elements of being successful in any sort of business dealing that may take some form of Negotiation (Which most do, whether intended or not) is Understanding your opponent to some degree... For Obvious reasons..Or Maybe Not to some..

Next is attempting to set a tone which tilts the objective or/and the outcome in your favor, which is effectively obtaining the best possible deal for You are whomever you Represent!.. that Having been said, there is absolutely positively no way as a skilled businessman you could not gauge how the tone you were setting from the beginning,on this Forum in particular, had trouble written all over it, which, I guess is why a Lot of Folks are questioning your Legitimacy as a Businessman of any sort...

Listen Buddy, I'm not here to bash you or anything just trying to maybe shed
a bit of light on this situation which has quickly become out of control ...

Now, I mean, you had to know ..
Wait, Before I get to That let me just say I understand the whole "These are my terms"
and Full disclosure Thingy...
(Payment will be made once the program has been FULLY tested and working as requested, I have no
bot/programming experience, so you need to bear with me and guide me through. Sorry, no payment before delivery of product, do not ask.)
... I really do get it, you wanna be up front about your terms and stance...But as a skilled businessman you must also know there are what is call levels of disclosure and when particular pieces of information should even be disclosed and/or discussed, it lessens that information's ability to kill the said deal or negotiations before it has even had a chance to get legs under it...

Information like..

"Sorry, no payment before delivery of product, do not ask."
INSTANT RED FLAG By the way, Plus the "do not ask" part coming from a relative UNKNOWN on the forum would be viewed as excessive and uncalled for...Overkill !!... like a private giving Generals a command. Now I must stress I am neither condoning or condemning here, I'm just saying this is how it was probably viewed.

Maybe the payment part should or could have been discussed at second level of negotiations.. one on one.. under the special circumstances, that being, you are well aware that this is GROSSLY Under bid for a project of this Magnitude and I think one on one if you were to tell said Programmer..

" Hey I respect what you Guys do and realize that what I am asking is worth far more than I am offering but I'm asking you to work with me here and I'll look forward to working on future projects in which I'm certain I can pay you a lot closer to your works worth"... or something to that effect...

You probably would have gotten better results..Which I'm guessing is the whole objective.
Nothing wrong with showing a bit of respect and recognition, not to mention a smidgen
of humility...

NEXT..
"Long time reader, first time poster, if you are not comfortable with that, don't reply."

Even though I'm sure you meant no harm but this can kinda come off as being a bit condescending in a community that is, well, kinda reputation based..
whether we like or not..It is what it is..You have to recognize the venue or arena in which you are playing if you are playing,or in this case posting to multitudes of people at once...
Also, the publicly stated..
"Also seeking for long term relationship on different projects."
Has kinda become a calling card lure of scammers...lol
Not saying that you weren't being genuine when you said it...:(
Guess what I'm saying is, it's probably not what you said Per se, as much as how it was presented..
Yes, even though it was posted in the Freelance dept. there is still a level of forum decorum that is expected to be respected...

Nothing wrong with being confident and firm in your stance but you have to also Except that this can sometimes be to your detriment. Case in point..

Good Luck Buddy, you have a great day