Handover Activity Not Done in Notice Period - what action I can take and how?

Hi, I was working for a reputed company as a Unit Sales Manager. I was on probation when I resigned, so only a 7-day notice period needed to be served. I completed that, but on the last working day, I did not discuss anything with my manager because of a little conflict, and the handover did not take place. Now my manager is not giving department clearance for F&F. So I have the same thing in the mail. In reply to that mail, he has asked to get confirmation from the channel partner that there is nothing pending from their end, which I have provided. However, he is still not approving the clearance. Please suggest what action I can take and how.

No company of the size you are referring to will be working solely based on the words of a single person.

You have done everything, now just escalate the matter with HR and the HR manager. If possible, also escalate it to the department head or CXO to whom your former manager reports.