One way to get around being called by an impersonating cop/incometax officer/judge/cbi officer is to ensure that your calls are screened. Either use a caller ID based authentifying app like truecaller - or restrict picking up calls from unknown users (this might not be feasible for people in business and those working with sales leads - but still). My phone is set to phonebook only - no irritating spam calls. In case there are persistent calls from a single number and it seems genuine - I just whitelist it (again with the caveat that this won't suit everybody)
In case of any issue regarding wrong doing in the past - there will always be written summons sent to your address either by banks/income tax/cbi/judiciary etc. Acknowlegement of summons is an important part of the judicial process.
