What if vendor does not charge swachh bharat cess on invoice

If service provider is liable to pay service tax to GOI, then you need to be worry about this. And you can account for bill as has been provided by the service provider.

The service provider is expected to charge the SBC. If he does not do so, it is his liability. At best he can be informed that he is not charging.

The service reciver cannot be expected to advise and rectify the tax compliance of the vendors.