You usually pay the fee at immigration once the paperwork is approved. Probably an officer will go through it and tell you if you're missing anything on the checklist long before it's scrutinized again, stamped approved and you pay the fee. YMMV
11 million Wise users following the rules, a few crypto kids playing fast and loose whine when the plug is pulled and they can't get instant gratification.
Keep the original and provide explanation. Your visa has been issued, it's a done deal. Doubtful that you'll be questioned that deeply unless you are applying in country for an extension, which isn't recommended.
After the interview you should get the decision fairly soon. Surprised they didn't tell you the answer at the end of the interview. If approved you print out your visa, grab your passport and head to Thailand.