the bank must have given a reason why they suddenly do not issue the bank letter (I suppose you mean that and not the statement?) which everyone needs and is compulsory in all IO for extension of stay
Does anybody know how tenants could be fined if they don‘t register TM30 in time? I do mine myself, because I travel around so many times that my landlady asked me to do it. But sometimes after a short 2 days trip to another province I simply forget it.
If it said on the app that mobile banking is suspended due to mismatch of account name and phone, then its only the app that doesn‘t work until you settle it as requested.
You can test it by asking a friend in TH to transfer you money to your account.