Transfer to another office while on maternity leave

Madam/Sir, I am working at SBI in Delhi Circle.Currently I am on maternity leave.My employer relieved me of my duties during the leave period to report at another office so as to get my further assignments. Earlier I along with two other batchmates were confirmed from backdate in the services and were awaiting for our postings. I had already informed the HR that I shall be proceeding on maternity leave from 01.11.2015 for six months and it was duly sanctioned by the local head office, please give me my posting beforehand but they did not respond and relieved me during maternity leave. My questions are 1. Whether they can relieve me in between of this leave to report to another office and can stop my emoluments and lease rent etc.? 2. Can I extend my leave for 2 months extra in a stretch? 3. Shall I be eligible for being part of promotion exercise and give promotion exam during this period? Regards M Sharma