I couldn't catch my flight 2 weeks ago and the Thailand Pass phone is never answered. My advice is to call your nearest consulate, they have direct contact with the government in Thailand and they can put pressure to make the change.
At the Thailand Spanish consulate, yesterday they confirmed that they could make the date change, but, today is the weekend and I can't contact them until Monday.
Hey, they give you internet access to the bank account or to the app? I opened 2 years ago the same account but they don’t give me the access from internet. They said that there’s no internet access for this type of bank accounts.