Dear Chetan Jadhav Ji,
The sword of uncertainty is hanging over the issuance of notification in this aspect. Whether will it be issued retrospectively i.e. 1.7.17 or not nothing can be said at this moment, especially, keeping in view health crisis in our country. This health has effected economic condition of our country. Govt. may issue notification regarding charging interest on net cash liability but no hope of retrospective amendment. If issued, it will become a precedent.
Sufficient detail has been given above. Refund claim can be filed under Section 54(8)(e) of CGST Act which is extracted below,
"Section 54 (8)(e) the tax and interest, if any, or any other amount paid by the applicant, if he had not passed on the incidence of such tax and interest to any other person;"
You will pay interest from your own pocket, you can prove that you have not passed the burden of tax/interest onto an other person and thus you will qualify to claim refund of interest. Lodging protest with the department means no time bar limit will be applicable.
Write a letter to the jurisdictional GST Range officer along with a copy to the Deputy Commissioner, in charge of GST division. Mention the details of amount paid under protest, challan number etc., and also give remarks in the letter as under
“This payment has been made under protest. We do not agree with the views of the department..
Get an acknowledgement along with sign and stamp of the office, along with name of dealing official mentioned therein.