Politely, you're a head case op... this is how I read it:
them: “congrats by the way for the promotion, dint see you before the end of today”
me:”thanks. I appreciate it.”
all good.
them:”yeah you deserve it. If you didn’t get it I’d be annoyed. I’d hand in my notice because it would be a really poor choice”
even nicer, affirms that they really wanted you to get it.
me: “I’m happy. But we both know this was offered because I didn’t get the lead role I initially applied for. You know that though. You’ve been here long enough”
You all of a sudden putting a negative spin on it saying you only got in to compensate for something else.
them: “fair play but I didn’t get my first promotion for 7 years in”
them, understanding your point but saying you obviously got it for a reason as they don't just hand out promotions, they themselves didn't get one till they had worked there 7 years.
me: “you misunderstood me. I’m very happy I got it and I appreciate it. I’m just saying I know how my role came about”
you: on the road to mental town
them: “you better do. If anything I would always back your cause”
them: you should appreciate it, they don't just hand out promotions willy nilly and you deserved yours.
me: oh come on. You’re misunderstanding me here. I’m not being unappreciative. You’ve seen all I’ve done while my manager has been away. I’m happy I got the role. I’m just saying it’s because I didn’t get what I initially applied for I was offered this. I feel I’m being told off here”
you: sdfhskfuxcyvohasrefguhfuiogdufidyhfvuiofgsug
I think you seriously need to work on your communications skills.