Can I retire in Thailand with a Non-Immigrant O Visa instead of an O-A Visa?

I am an US citizen who wanted to retire in Phuket. I got a non- immigrant multi entry O visa from the Thai Embassy in NYC. Expires feb 2020.

I have been inPhuket 3 months now and am struggling with immigration. If you can help me understand the below I would greatly appreciate it.

1. From what I have read on these forums and web -I should have gotten an O-A visa. Not O. Is that correct? ( O is for spouses or volunteers?- not retirement?)

2. I cannot find a bank that is willing to open an account for me because of point 1 above. Has anyone ever opened a bank account with O visa? If so which bank? I have tried 3 so far- Bangkok, kasikorn and Siam all said I need O-A.

3. My understanding is I need a bank account here to place 800k bht in order to extend my visa once it expires. Is that only true for O-A?

Thanks for advise.