Leaving the original fee - as others do - in the script or doing a one-time payment clears this situation.
I've contributed the script to the publicity in order for a compensation and thereby keeping the service alive.
No it's not considered stealing. What service are you keeping alive? I could (no offense) care less about your personal faucet. You don't deserve compensation for what is, at this point, considered to be a new application. That compensation should be, and currently is, mine. Read your own license in your GitHub if you don't believe me. I have done no wrong, and the real members of the open source community will back me up. If your license doesn't prohibit something, I am free to do it as long as it is open source. I made a legitimately useful derivative work of yours, which I believe is better, and I can do whatever I want with it. If people want to modify yours to include my functionality, they can and I have no problem with that. But if they want to use my pre-created one, that's their choice to make. It's not like nobody else can do what I have done. I am just dedicated to make it super convenient to switch.
In addition, I created more useful features that people may want in a faucet, and have fixed your buggy code quite a bit (although there is still more work I need to do on it).
At all, part of the compensation should belong to me because the most part of the script, the structure, is coded by me and not your. Mentioning "hard work" is the wrong way.