(Co-founder of Bitonic here.)
This is not unusual for Dutch banks, ING in particular. Although we as a company have good relations with them (as a long term customer), transactions to/from bitcoin are still considered high risk by them.
Automated systems still sometimes block transactions to us, contacting your bank (ING mostly contacts you, other Dutch banks mostly don't) and asking them to deblock almost always works.
If you keep experiencing problems, please contact us so we can address these issues with the bank directly.