Realistically if you wish to live in Thailand long-term, tourist visas don't cut the ice. You're going to have to look at strategies (work, education, elite) which allow you to remain on a long-term basis
YouTube videos are harmless. People are posting them in their thousands. You won't get any attention UNLESS you post something which criticises the government, Buddha or the monarchy. Stuck to tourism and nobody's going to take a blind bit of notice
If you have been rejected for the insurance you can apply for the OA using the value of assets in your home country provided they meet the same value of the required insurance
Credit Card companies won't get involved in any discounts which are outside of what was actually spent on the card, and it appears this has been fully refunded, so there is $0 to chargeback as the full amount has been refunded. A consumer affairs authority would be the best avenue