Yuck - management sucks, the union sucks, and you're on your own. You can't sort out management, and the union wimping out leaves you without the ability to face it collectively. Actually, manufacturers costings based on contracted training credits can be far worse than your local TRTO who have to compete with others. "How much are my training credits worth?" can easily generate an inflated answer.
The only solution seems to be to stop paying your union fees and use the money saved to pay a solicitor who knows local and EU employment law to advise, being in the EU could make a big difference. Or/and you could try contacting IFALPA individually, as they could have some European law having lobbied on behalf of other EU ALPAs, or possible legal precedents from other unfortunates in other EU countries. It's not just the amount, the time period and non-reducing "contractual penalty" are all worth running by a solicitor who knows employment law.
Good luck.