Try a different bank branch, or as some here say, a different bank.
There are no such requirements - by law - to open a bank account. Your particular branch does not want to do it, that is why they sent you to get papers the immigration office likely has no clue about themselves (except for the TM30 of course).
Some people here are bad in explaining it, e.g.
@Brandon ***********
- a TM30 is not useless. You correctly point out, that he might need (that is not really required, but he might need it) a "residence certificate from immigration".
And for that you need a TM30, oops. Obviously you would get/do that in one go at immigration.
So, "@ Jacki Catlin" if you have to go to immigration anyway, then get both the recipe for the TM30 (you need that long term for nearly any interaction with immigration, anyway), and the residence certificate. (You hand in a TM30 form, simplest from a hotel, then you basically have the complete TM30 recipe already. OR: you have to do one with your landlord, and you get a recipe for it, the recipe is what you need).
Electric bills etc. are not needed.
Regarding your Thai SIM, get a simple cheep one at
****
or Lotus. Something like 50GB/70GB will start around 220THB a month. Their prices (AiS/TRUE etc.) are very similar but the behaviour if the data option is exhausted, when you top them up again might be different (and complicated in some cases).