Cheryl,
Your BedBug infestation is probably quite severe.  The fact that you’ve seen them crawling on your wall indicates a large problem.  Bedbugs in nature are very elusive and rarely spotted.  Not to scare you, but I promise you that you are being bitten by bedbugs every night.  (Probably dozens of times, if not hundreds)  You see, you are lucky because only 50% of people are allergic to bedbugs.  What that means is that you are being bitten, but because you are not allergic to the saliva or anticolagunt you do not show the red itchy spots that the other 50% of people do.
I mention this as I noticed your comment states that you you have a minor problem with bedbugs.  When in reality, if you have bedbugs– its never minor!   I would not agree to pay the $250 unless you can get management to sign a document stating that you will not be held to any further cost associated with bedbug treatment.   I mention this because if they are hiring an exterminator for just $250, it means they are using a non-effective chemical treatment.  Havard University did a study on chemical treatments and was able to prove that the chemical sprays are only effective on adult bedbugs and do not kill eggs, further they were able to find that after multiple treatments the bedbugs became resistant to chemical treatments.
I can understand your concern about paying for the treatment, in fact that responsibility may not be yours at all.  Honestly, I don’t know the legalities behind whether you can be held responsible for bedbug treatment or not– I do know a ton about the little critters, just no the legal stuff.  

Hope that helps,