The team lead of a project in my company got promoted to Project Manager and one of the oldest developers who worked for 2 years on the project expected to become team lead. I worked in a different team at the time as a developer (and had got bored of the project) and had coincidentally asked my department head if there was any other project I could work on.
Turns out that I was up for a promotion that year and he promoted me and made me team lead of the other project even though I'm not very familiar with the technology. The developer who had hopes of becoming team lead and a few other developers who felt that she should have been made team lead, are now doing their best to humiliate me whenever I ask questions about the technology which I don't know much about. She and other team members also make it a point to spread humiliating comments about me in the gossip circles in the company. I'm struggling with a health issue because of which I'm finding it a bit difficult to cope with learning the new technology too. The team does not even share necessary technical information with me. The project manager tried helping me out in the beginning, but now even she seems to side with the team.
Speaking to the department head about the teams behaviour seems to provide no result, since he trusts the project manager and wants her to take necessary action. To me, the advice he gave is
"I work with people with the belief that they come to work to do their work rather than to engage in politics. If people aren't following your lead, talk to them and find out what is troubling them. If they won't follow what you say, then change the interface. Let someone whom they won't mind interacting with, interact with them, and you give the orders through that person. But don't give up your position as a leader"
What do I do in such a situation? I've tried winning over the team by being considerate but they refuse to accept my lead and are adamant. I've tried talking to them individually but they use the opportunity to insult me. The project manager is the only "interface" that I can use, but she's got her project managing to do, and she can't help. Perhaps the question I should ask is, how does one handle a mutiny?