I was recently terminated from my last employer of over 2 years who, after being let go, has lied about my position title. I started at this company doing inside sales, helping w/ wine tastings and misc. office work. The position quickly evolved to planning events, wine dinners, being in charge of their wine club, creating sales and promotions, creating press kits, doing some PR, marketing, creating POS, working w/ advertisers on signage, etc. at events, going on some sales calls w/ new reps, etc...a huge list of responsibilities; I was even sent abroad to visit the wine producers.
Clearly NOT the job of an admin. assistant, which is what my employer claimed my position was after leaving when she tried to deny my getting unemployment benefits, so she wouldn't have to pay anything. She claims that I gave myself the title of Marketing Manager, not true. There is no documentation of admin assistant being my position; furthermore, she hired an admin to help both her and myself with all the work that was piling up.

When filling out a workmans comp insurance form, she spoke with me about my position and it was that of marketing coordinator, something she wrote down on the form. (Is there a way I can obtain a copy of that form for proof?)
Also, a little after a year of working there, my manager introduced me to a few people, at work related functions, as the marketing manager. When a woman at a non-profit wanted to partner with us, my boss introduced her to me as the Marketing Manager and said Icould help her out.

Basically, I need to know if a verbal change in position title(there is nothing written) constitutes as a formal change (given my situation described above)
The only thing I have in writing is the workmans comp form, if I can get ahold of it.
I put Marketing Manager on my resume since that is what I was refered to as. I am concerned that my former manager may lie about my position to potential employers and need to know what I can do to prevent her from lying again.

Please help. Thank you.

YOU changed your title. Your boss may not even have noticed it. Especially since it was on a form that was incidental to what position you held. If they want to call it Marketing Coordinator, they may. I would not overstate my title on a resume, ever. Managers are different from coordinators. Your duties are what are critical in pursuing another position.

My Manager is the one who called me and refered to me as a Marketing Manager, so does that constitute a title change? That is my question

I did NOT give myself that title. I only used it after she refered to me as the Marketing Manager.
Basically, there was no offer letter and I was assigned no formal title at the time of hire; it was all verbal. Same thing with the Marketing Coordinator title; all verbal except for the workmans comp letter mentioned. Does that hold burden of proof as to what my title was? Or can she continue to lie and call me admin assistant.

Thanks for the help!

You need to show your title as whatever the company records show. You can always explain to a prospective employer what your duties were. Title is not all that important in the grand scheme of things.

Patty MD is right,the job title itself is not important, what matters are your duties and responsibilities.