Hello, i just got Denied to Entry in BKK.

i was in Thailand, on a Non-Imm ED Visa with a lot of Covid stamps almost 2,5 years. on the 25.3.22 i fly to Cambodia, i apply for a new Tourist e-Visa , and made Thai Pass and everything. I had a Paper from my School, that proves, i came back on Tourist, just for can change to my new ED-Visa inside of Thailand to learn Thai. However they did not let me Enter, because they said i stay in Thailand for too long. And put me in the Airport Prison for 2 days, and today i had to fly back to Cambodia. What i can do now, to come back to Thailand. Any Suggestions ? TIA