s.guo82, I'm really sorry for your NER.
Do you mind telling us exactly what letters you submitted for your work experience? If I'm not mistaken, you mentioned that you claimed 2000+ hours only on your taxable portion. Since the taxable portion for most of us is usually the TA, I'm actually wondering how you could claim so many hours on taxable income alone. Or maybe your RA is income also taxable (which was not the case for most people here in this forum)? At least what we know for sure is, the reason for your rejection was not that you did not have continuous one-year of full-time work experience, so we know that they consider your TA/RA experience as legit work experience.
Also, how many years have you done your PhD? Maybe if you tell us the breakdown of your work experience, we can work something out, but I still doubt that PhD RA/TA alone can give you more than 3,900 hours. If you have only done a little over 2 years of PhD, then claiming 20 - 25 hours a week, the most that you can claim is probably around 2,500 - 3,000 hours.
If you go back 10 years from right now, do you think you can accumulate at least 2 years of work experience (3,900 hours) of skill level 0, A, or B? Was your Master's degree paid, or was it self-funded?
Anyway, I suppose your NER confirmed that adaptability points are only awarded for those who completed a program of two years, not having completed two years of the program. I suppose that's the reason why they didn't just make this PhD stream a stream of CEC rather than FSW (if you notice, all categories for CEC would have been FSW with more points than 67). What a bummer