how can i lock settings

Yesterday I connected with apple support and I am not sure she was legit. She was argumentative but not rude. She just would not listen to anything I had to say and responded with the same answer. She even said that for my issue I would need to contact Apple….. wait I said then continued with Don’t you represent apple and helping isn’t your job? What do I do I get rerouted for everything and disconnected when I try to search or call for support no matter what company. I also can’t find my emails then they show up the next day and it’s either confirmation codes or apple support saying they missed me when they called or my Face ID was turned off well stuff like that. Also someone used my credentials to make themselves a approved to make changes like the person who owns the account then changed my daughters T-Mobile account completely