Another interesting piece on the matter:
Πώς κατέρρευσε η Tripsta: H αλήθεια των ισολογισμών και τα υπερπολυτελή γραφεία (νόμιζαν ότι ήταν η Google)
Basically it seems that, while they are blaming others at the moment (eg travelport), they were basically already bankrupt from 2015 onwards. However the lack of oversight in Greece still allowed them to continue for more than two years, even though it was clear that this was the only possible outcome. It only increased the debt even more.
I have no doubt they will go fully bankrupt soon. Without a source of income they will not be able to pay back these debts to the airlines, thus, airlines will try to limit their exposure - meaning they will stop honouring unflown tickets soon. Their plan to become a price comparison website, and use some refunds coming in from Amadeus is, quite frankly, ludicrous...that won't bring in the amounts that they will need for outstanding tickets.
They were doing 740M revenue per year, I am wondering if that means that they will have - besides the 70M already outstanding bills - another 300+ million of unflown outstanding tickets...
Its a classic tale of living (too) large, gathering huge amounts of debt and in the end skipping the bill and screwing everyone else in the process.