不但不…反而…: not only not… but on the contrary
复句 / complex sentences
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
This pattern expresses a result contrary to expectation: you expected X, and not only does X not happen, the opposite happens.
不但不 / 不但没 denies the expectation, and 反而 ("on the contrary") introduces the surprise. It is stronger than 但是: close to English "far from…, it actually…".
With one subject, put it before 不但. 反而 is an adverb: it goes after the subject of the second clause, never at the very start of the sentence.
Examples
吃了药以后，他的病不但没好，反而更严重了。
Chī le yào yǐhòu, tā de bìng búdàn méi hǎo, fǎnér gèng yánzhòng le.After taking the medicine, instead of getting better, he got even worse.
我帮了他，他不但不感谢我，反而怪我。
Wǒ bāng le tā, tā búdàn bù gǎnxiè wǒ, fǎnér guài wǒ.I helped him, and instead of thanking me, he blamed me.
雨不但没停，反而越下越大。
Yǔ búdàn méi tíng, fǎnér yuè xià yuè dà.Far from stopping, the rain got heavier and heavier.
Common mistakes
✗ 他不但不累，而且很累。 → 不但不… pairs with 反而, not 而且 (which adds in the same direction).
✗ 反而他更生气了。→ ✓ 他反而更生气了。(反而 after the subject)
✗ Leaving out the negation: the first clause must contain 不/没.