Today while trying to get a tourist visa extension I was told I needed to bring with me the copy of my original eVisa letter.
Of course they told me this after I waited around for 2 hours. I think the lady was being difficult because of my visa history, or perhaps I was feeling sorry for myself. She made some comment, I couldn't make out, about "you stay long time in Thailand". Those of us who do many visas maybe the new step-child.
If you're trying to get a visa extension (or any other immigration business) I recommend bring ALL possible paperwork, flights, hotels, etc. Nothing is too ridiculous, apparently.
On the plus side, I was able to do the TM30 like 5 weeks after arriving to Pattaya. I don't full understand how all of this works. When I rented my long-term room I paid somebody there 200 baht, they filled out some paperwork on line printed, copied my passport. I thought I had completed the TM30, but it turns out I also had to give some paperwork to immigration. I gave them that paperwork today (5 weeks later) and they were cool with it.