What should I do if the Thai immigration requests additional documents for my visa application?

A user is seeking advice after receiving a request for additional documents concerning their visa application, which has already been pending for over a month. They previously submitted a letter from their accountant detailing their business and income. Comments from the community suggest that the authorities are likely asking for a certified version of the letter and possibly require verification of the accountant's credentials. Other advice includes ensuring the correct submission format and providing a tax return.