If embassy don't certify income, then the proof of 65k a month being deposited in your bank for 12 months is the proof you use to get an extension? Can't blame Thailand for your embassy rules.
Surely it's the type of contract for that SIM that counts? I can't use my UK SIM in Thailand without huge cost so I don't use it and use Skype. Just load a few ££s on it.
we have never overcharged for electric and water. It's charged at govt rate. Meter is read on arrival and exit. You're assuming everyone's a crook which is not true.