How can I renew my Non-Immigrant O visa before it expires on July 2nd?

Okay, SO you HAD a valid 90 day stamp that expired May 20, which means you went automatically on amnesty and this post I already posted to you is the correct answer

So your VISA sticker expires on July 2 ?

What is the expiration date of your current entry stamp? <- the rectangular stamp they gave you when you stamped IN to the country?

Alright, IF you have a year-long, multi-entry Non-O visa <- the kind where you bounce out and back to get a new 90 day entry stamp and your stamp is expiring you will automatically go on amnesty until the 31st of July. and before you ask the answer is NO, no one knows what will happen when that amnesty ends because the government has not written what happens when it ends yet.

IF they can get the borders open AND your VISA (the sticker in your passport) is still valid (and you meet any possible new entry requirements) you can bounce out and back to get a new 90 day stamp.

OR

You can go to the imigration office and get the hand out that lists the requirements to get an in country yearly extension of stay based on the reason you got your Non-O visa (retirement, marriage to a thai, etc) Meet the financial requirements, turn in the documentation and get a year extension.

OR

If you're married to a thai or have half thai children here you could also apply for a 60 day visit thai family at the immigration office as well, and that does not require proof of funds.

There must be reason why you got this Non Immigrant O visa, visit the Immigration Office and apply for a 1 year Extension of Stay based on the same reason.