1) Tokensuite has been very helpful. They contacted Crowd Machine and they did get a response from them. Basically Crowd Machine explained that an authentification was needed because there had been suspicious changes on the spreadsheet, but they didn't explain why they ignored my authentification messages.
2) I saw that Crowd Machine would be present at the Amsterdam Blockchain Expo at the 27th and 28th of June and saw perspectives. I sent them the following email (through their contact form):
With pleasure I took notice of your news letter where it is mentioned that Crowd Machine will be visiting the Netherlands at the Blockchain Expo in Amsterdam at the 27th and 28th of June. Booth 138; a number to remember.
You are creating for me the best opportunity to expose Crowd Machine as scamming me, as has been proven at https://bitcointalksearch.org/topic/solved-crowdmachine-not-paying-my-bounty-4489085.
This time there will be no opportunity for Crowd Machine to ignore me because camera's and / or me will be right in front of your nose. I am going to contact specialized press such as the Dutch TV show 'Opgelicht' (translated 'scammed') and other press. Ultimately I'll be personally in front of your CEO's nose and that would probably be the worst case scenario regarding PR & marketing.
The other scenario is that Crowd Machine simply and fairly pays me the ETH to which I am entitled for the work I delivered. $1156.666252 in ETH at address 0xbF6b6F17eC2cDC4FF6406634747F36Ab4837682c. Otherwise a rollercoaster expo in Amsterdam awaits.
It is tomorrow that I will contact the press. So Crowd Machine only has today to settle the matter. Something which should have been done in honesty from the beginning anyway.
Regards,
Arvin Das
Only a few hours later I suddenly did get a response from Anne at Telegram.
Anna states that she had not been reading my messages. This is however not convincing. When messages are unread a blue dot appears before the sent message, as shown below (tested with my other Telegram account). And my screenshot of my messages to Anna in the opening post clearly shows that she has been reading my messages.
After promising to email me on the 26th I received no response on that date. So on the 27th I reminded her that I would confront Crowd Machine's CEO with this case in Amsterdam. (See below).
The next day Anne promised me to pay me within a couple of hours, and this indeed has happened.
This means that my scam accusation can now be withdrawn.
About the sincerity and correctness of Crowd Machine in this case the reader can judge him-/herself. I have my own thoughts about it.