Since I'm relatively new, I'm not quite sure if this is the kind of thing I can expect from co-workers at the post office.  Please let me know how you would handle this and if I can expect plenty more where this came from:

Here's the scenario:

On one of my matrix routes there's another co-worker, we'll call her Mrs. X that has seniority over me.  The regular on the route has been out quite a bit over the past couple of months.  Mrs. X has another job where she cannot always work the route and that's where I get called in.  One day this past week I got the chance to work the route and she had worked the route for several days beforehand.  When I got in to work, the regular carrier on the route beside mine let me know that Mrs. X had left plenty of mail for me from the previous day.  The carrier pointed out LOTS of mail that had been left....some of it I would call "undesirable", awkward to carry and such.  I asked the carrier if it had been particularly busy the day before and she replied "NO".  She said that Mrs. X does "that" to her all the time and that she wouldn't carry that mail, just case it when I returned for her to carry the next day.  I seriously thought about it but ended up having to do it anyway because I received some Express Mail and there were truck issues, etc.  When I got into the LLV, the thing was on EMPTY and while out on my route there were so many misdelivered pieces and miscased pieces (that she had thrown) that I couldn't even believe it myself.  Mrs. X came by the office and came by the case to speak to me, making up some excuse for being at the office.  She obvioulsy was checking up on me because she was nervous about someone riding with her the next day for mail count.  She told me what I should carry and what I should case, etc.  Then she called me out on the route and left a message on my cell phone reiterating what exactly I should do.  Needless to say I did what I would normally do but I just about decided to tell Mrs. X that if she ever left me a mess like that again, I would go to the supervisor.  I like to think that I try to be considerate of any other person that might work the route I'm on the next day.  I try to always gas up the truck and case all I can, even if it means working extra and for FREE.  As I told the other carrier, I don't mind working but I will not put up with being taken advantage of.  This Mrs. X has my cell phone number and is constantly bugging me whenever she needs something.  She'll have me tell the sup whenever she can't work and has me check her schedule while I'm at the post office.  Acck!  I've gotten to the point where I won't even answer the phone when she calls and will not return her calls.  I do have to say that where I work there are PLENTY of RCA'a and regular carriers as well who have taken me under their wing, so to speak and have given advice, offered their help and generally watched out for me.  I was always surprised at how the majority of them will recognize someone who is a hard worker and will do everything in their power to help them.  I hope that one day I can do the same for a newbie like myself.  It's sad that Mrs. X has to be there to try to take advantage of the newbies.  What can I do?