Could be an updated security policy, happens with my US accounts sometimes out of nowhere I can't log into the app because I'm outside the US, sim card # is different, idk.
If you're not able to call them, try transfering $1 into the account and see if it goes through. If it does, then it's still active. Also, if you're applying for a Non-O outside of Thailand, the money doesn't need to be in a Thai bank. If you're going to enter on a tourist visa and apply for a Non-O in country, the money doesn't have to be vest, just be in your account the same day you apply. I'd just wait until you come over to deal with it honestly.
If there's money in the accounts, they'd still be open. Most don't realize you get yearly interest payments deposited into your account automatically, which for me covers the cost of the monthly maintenance fees meaning I never loose a balance if I don't touch the account.
No, if you have a Multiple Entry Tourist Visa you'll get 60 days everytime you enter, land or airport. If you enter on the last day the visa is valid for, you'll get 60 days also.