SCB Easi Pass is the only account I am aware of where you can keep the 800k that pays decent interest - otherwise its back door agents, bribes, and the risks that entails…..
Try opening a bank account in many other parts of the world, especially as a foreigner - tedious and painful….its a widespread problem not exclusive to Thailand.
Which immig, most offices have webpages set up by the volunteers, Phuket Immig has the list you are looking for on line under Phuket Immig Volunteeres web page.