I submitted my application in SINP 2018/01/01,and after a month my status changed from "application received" to "in process".unfortunately,I got an email from piu asking about my application fee which was paid using a credit card that is linked to multiple other application in their system.I sent them a cover letter explaining the problem but they haven't answered yet,I really don't know what to do....can any one help me?how long should I wait?