Why do you need to even travel if you don’t have 500k baht or $15,000? Stay in your country, work hard and save. When the time is right, travel stress free and with financial security and responsibility.
I think it will be much better to stay in your country, work hard and save money. Once you have the financial means to travel independently, then proudly start exploring the world. Given your current status, I think it is too soon for you to obtain a DTV when you rely on family for financial assistance.
Does your passport’s issued date correspond with the matching photo you submitted? Is it really within a month or two? It is possible the immigration staff barely checked and rejected your application. Unfortunately once rejected there is no way to reinstate your application. You have to start over and pay a new fee.
Even when extending for a month after your two month visa is sometimes complicated and confusing due to language barriers among all the parties involved. Meaning your landlord, the immigration staff and yourself. So when renewing a DTV, that means 10 times more confusion and complications. So it is best just to do a border run, enjoy a new destination for a week or two and come back. I know we all love Thailand that we don’t want to be away for a minute, but let’s not be cheap Charlies and do what is simple and stress free.
Sometimes they just randomly select an individual or two for a little extra screening from all categories, they could be even platinum thai elite visa holders. It is just a safety protocol that is common in all countries’ airports and they do it to their own citizens as well. This time you happen to be the one selected, there is nothing wrong with that. Just cooperate and handle the situation politely and you will be on your way.