I currently work in a small office with several people most of whom are not in the same department as I am. One of whom have been with the business for quite a while and act as a mouthpiece for my manager when he's not around (since most of the other staff are on the other side of the building) but she is otherwise an secretary/admin type. This results in 2 primary issues: Firstly, they are under the mistaken impression they are my supervisor and secondly, they attempt to "help me" do my job.
It's the second issue that I am concentrating on as I am making some headway on the former. The helping issue is one that I find incredibly frustrating. I find that this coworker will interrupt me in conversations with clients in order to "correct" me (which then often requires me to correct their correction), will hover over me if I am on a phone call or try ask me to do things that are out of scope for my position (to give an example, one of the sys admins got chewed out for bringing up a desktop they noticed BSODing to our department because we are paid to do that, not them. due to this level of strictness even simply requests I have to deny as I learned quickly).
Now, what I find the most frustrating thing about this is her corrections are wrong, her hovering distracts me and if I decline to perform her requests she tells me that I am lacking in customer service et cetera. On top of this, I am highly qualified for this position and they have a cursory knowledge at best.
So, the question is this:
Is this an issue that I should take up with them personally, or is it best I contact my manager and get them to clarify? If I approach them, how do I go about it?
I am hesitant in involving my manager as I don't want it to seem like I am out to get this person, I simply don't want/need their "help".