What does the change in designation implies: Re-designation, Demotion, Promotion etc?
Is HR competent to do so?
Who maintains the Pay Portal: Payroll, HR?
Who has to authorize to any change in pay portal?
If HR is not responding then don’t remain entangled with HR. HR personnel are just another employee like you.
Escalate to good offices of appointing authority, MD, Chairman (and make them a party) and proceed further after getting a reply.
Do you have a copy of HR policy, Service rules and regulations etc mentioned in appointment letter?
Download copy of all policies/rules etc and preferably attach these with communication sent by you.
Such matters are personal and can be sent from personal email id and may be sent preferably by letter thru Redg. Post.
You may also download any other fact, document etc that is relevant and useful to you.
If there is any employee’/Trade Unions/GRC/Works Committee then you can approach them too.
You are in the organization and closest to the facts and if you smell any foul play firm up your next venture ASAP, and approach your Labor Law Consultant/Service Matters Lawyer/Law firm NOW and proceed further under thier expert guidance!