17-18 wrongly file GSTR1 B2B to B2C

Disclosure of B2B sales as B2C is an error which can be rectified till sep return of next FY. for FY 2017-18 it is Mar'19. since date is over, no more rectification is possible.

sincw you have alreasy paid tax to department you are not liable to make payment to vemdor again neither vendor is liable for tax, interest of same to department.

the vendor can submit your invoices to department as proof of tax being paid and department has no right reject, also note in circular 59/17/2018 related to input refund on export of goods or services, the department clearly mentioned that refund cant be denied on reason that vendor has not uploaded invoice if valid invoice from vendor is available.