No offense, but all language schools are only looking for NES (usually from the US or UK). Since that is what parents want if they are willing to pay 300-500THB per lesson. I gave you the technical details, but realistically, without a degree, and being considered NNES, your chances of getting a teaching job are almost non-existant. (Sorry about my initial comments, I thought you were from the US.)
If you mean language schools, yes, but most language schools don't offer a B visa and work permit.
(Also, TEFL is not considered as being much value in Thailand, and South African citizens are considered as NNES, even if I agree that might not be fair. You would be competing with NES from the US, UK, with bachelor's degree and multiple years of experience.)
If you're asking can I do something illegally, even if that means being fined, jailed, made to pay a $1700 USD for a last-minute plane ticket (and jailed until it is paid in full), and blacklisted from the country, you can answer that yourself.
Some schools/visa agents/forum members might suggest you can, but if you get caught you can be fined—and are deported and blacklisted from the country. Look into language schools or corporate jobs. 👍