This is an error that has been mentioned many times before in this group. Personally it seems stupid that they don't let you correct minor errors like this. But it is what it is. So, the only thing to do is either accept his mistake and reapply or attempt to dispute the charge with your credit card company.
90 day reports are a separate thing that are simply stating you are remaining in TH more than 90 days. If at 180 days you plan to stay over on the DTV and do it in-country at immigration, then they will ask for supporting docs. If you leave the country and come back they aren't likely to ask for anything.
They pulled me aside, but they mentioned it as because I was entering for the first time using the DTV. Not sure if they'll do it for later entries. Filled the form, didn't get asked many questions.
You have to go in person to the local Revenue office. I already have one from when I was working in my business previously, so I haven't done it as a DTVer, but here are the instructions found online
you could use a bank card for that, or if you really want to pay a ton of extra fees you can use a credit card at the ATM. But I really don't think that's enough to substantiate their reasoning behind not opening bank accounts here.
Anonymous participant 993 I can't speak to what's happening down south since I haven't gone through that way. Best to search the group for people who have specifically posted about that. I chose Chiang Mai as entry because I live here and it's just easier to take a direct flight. I suspect all ports of entry will gradually tighten up. Thailand tends to do "soft opens" and then gets stricter as they begin to realize the realities of what they created.