Grammar · Chapter 60
非但…反而…: not only did not, but instead
A 非但 不 / 没 B，反而 C
非但 is 'not only did not…'. If the second clause reverses the expectation it takes 反而: 非但没有帮忙，反而更乱了; if it simply adds, 还 / 甚至 do the job: 这家餐厅非但不贵，味道还特别好. It's a written pair — speech says 不但…. After a negation, don't drop 反而: 非但没有帮忙就乱了 sounds unfinished.
Examples
- 这项政策非但没有降低成本，反而加重了基层部门的执行负担。 Zhè xiàng zhèngcè fēidàn méiyǒu jiàngdī chéngběn, fǎn'ér jiāzhòng le jīcéng bùmén de zhíxíng fùdān. The measure not only failed to cut costs — instead it made work harder at the lower levels.
- 这家餐厅非但不贵，味道还特别好。 Zhè jiā cāntīng fēidàn bú guì, wèidào hái tèbié hǎo. This restaurant's food isn't just inexpensive — it tastes especially good too.
- 非但没有帮忙，反而更乱了。 Fēidàn méiyǒu bāngmáng, fǎn'ér gèng luàn le. Not only did they fail to help, it just got messier.