Hi, my sister came to Bangkok and had to apply the same ..2 times..the 2nd time I called the hotel to ask them to approve it as soon as they can, and they approved it in 8h !
My sister just applied for tourist visa, and they asked for the full receipt from the hotel and details of payment and whats included in the price. I would say you need the payment proof..
Some time ago I overstayed 2 days and paid the fine.. I did the same and went to Cambodia for tourist visa, I had no problems getting it.. the problem was when I arrived back in Thailand, they saw my previous overstay and interrogated me for at least 30 min.. they even called my boyfriend to check my story 😒😒😒
Officially and practically, the responsibility to report the stay of a foreigner rests with the host: the landlord of a property, the hotel or the service apartment. Delayed or late reporting of a foreigner can be penalized with 800 THB to 1,600 THB per person (normally the penalty does not exceed that amount, even if your landlord reports months too late).