Bank Swift Issue - Where/how to make a formal complaint?

I had an international swift transfer rejected 12 business days ago. The usual process for a swift deposit recall is 1 - 5 business days. 

As my transfer was in Euro, my bank used their EU counterparty, who in turn used their counterparty to send the funds. I've gotten the proper swift documents, MT103, MT199 and MT999. It shows the funds were rejected, and are with the EU banks counterparty, just stuck there. I've asked my Thai bank to find out what's going on with their EU counterparty, who have swift messaged them a couple of times, with no reply.

As there's counterparties involved, I understand it is not as straight forward as a bank to bank recall, but the communication with my Thai bank is far from great. I have to keep following up email requests with phone calls to follow up on email requests. 

Ultimately, my Thai bank has custody and is responsible for the funds and their chosen EU bank partner. 

If I keep getting the run around, are there any banking regulators here I can make a formal complaint to? Financial Consumer Protection Center (FCPC) - Bank of Thailand (BOT)?

Has anyone been through this process?

As the funds are on the Swift system, an automatic recall could take 6 - 8 weeks, possibly longer. 

I think the only way to move the needle is to first mention a formal complaint, and if nothings done, proceed with a complaint.