Think twice before digging in to deep in the 500.000.
In the past there has been big problems with foreigners, that couldn’t pay hospitalbills etc. if they got involved in a accident.
Under corona you had to show a medical insurance to overcome that problem of unpaid medical bills, but that did also stir up a lot of criticism and other problems.
But medical bills wasn’t the only finacial problem to be dealt whit, where foreigners misused the hospitality of Thailand, and to make sure those who make the problem also pay to solve the problem, Thailand now request a cash deposit, to cover those situations.
And they know that you had that kind of money, when applyed.
Banks in Thailand are like everywhere in the world, interested in having good stable customers, that have a permanent address, a steady easy traceable income, and use the account all year round.
That is why the banks are reluctant to give accounts to people on short time ( read: tourist ) visas, and who only spend part of the year in Thailand.
Don’t expect to get a residence certificat, until you have stayed at a permanent adress in at least 3 month, since that is what the residence certificat should confirm.
Furthermore the added attention on whitewashing of money, is an added burden on the banks, so reluctant depositing large amounts isn’t a guaranteed way to open an account.
The value of a resident certificat, had gone down, since Immigration Officers are giving them to people that are not on a longterm visa, or have stayed severel months at 1 adress in Thailand, so even if it is a formal requirement, the bank make up their own assesment of the stability of the want-to-be customer.
Be aware there is a error in the start of the article ( and several other copy - paste media with the same article )
A Thai Bankaccount has never been a requirement to get DTV, on the contrary it has been one of the big advantage over other visa, that you could get DTV as long as you could show 500.000 Baht equivalent in any bank anywhere in the world.
It has never been the intention that DTV visaholders should be in need of a Thai bankaccount.
The decision has been made, and only thing you can do is to apply ( and pay ) again.
Next time apply with the full amount on your own personal account, no doggy sponsoring.
They wan’t to know you are an adult person, that can handle things yourself
Why dont you read the embassy website thoroughly before applying there are important information to be found both there and in the manual on the e-visa website top right corner.