Dear member,
This is in addition to what Nathraoji has said.
Please note that most of the companies, while designing a policy on leave, include axiomatic statement at the beginning of policy and it is "leave is a privilege and not entitlement". Therefore, have you checked the leave policy of your company?
Whether this statement included or not, the procedure to avail of leave is to apply for leave in advance, get it approved by the HOD and then submit the application to the HR and then proceed on leave. Sometimes situation does not leave scope to follow this procedure. Therefore, companies show flexibility and allow the employees to proceed on leave and on resumption of their duties they can submit the application for the regularisation purposes. However, in such cases, before proceeding on leave employee are expected to obtain approval from their HOD.
Did you proceed on leave without obtaining permission from your HOD? Possibly, your manager saw your non-communication as effrontery. Hence the disciplinary action.
Thanks,
Dinesh Divekar