I always wonder, in what kind of situation this sentence would be useful...
Here is another case where this tense is translated not as 'we are not wanting' but 'we do not want'. OK I get that. So why not 'They don't make cakes in this kitchen' instead of 'They are not making cakes in this kitchen; for "Bu mutfakta pasta yapmiyorlar'? (I know it's the wrong 'i' but I can't access that other 'i' here. )
Seni is "you" in the sentence, the biz is optional at the start. You can tell it is "we" from the ending suffix "uz" without the need for biz.