Dear amarjeet,
There are many questions involved in this query
The most important point here is has your supplers sale case has been assessed at banglore.
Normal practice is when you are ( as seller ) not able to produce C forms timely then Sale tax authority's can grant time to submit C forms as per their discretion .
Only if sale tax case has been assessed and the excess time provided by sale tax authority has been expired & party has asked for C forms and you have not supplied the C form .
Then you must pay the Dues to the party . Otherwise Issue the C form accordingly.
( I think more then 98 % C forms issued by the party only after request from seller to issue C Form . )
Warm Regards
The main point for consideration here is that C form is required to submit quarterly by purchaser.
However , It is also the duty of the seller to collect the C form timely .