Hi, M.. Well, my advice may be of least consideration regarding this issue because I avoided this scenario by never introducing "binky" to my daughter. My neice went through serious binky withdrawal including screaming and fall-out tantrums which were followed by mad searches through drawers and cabinets and that was all the lesson I needed-when my daughter arrived 4 years later, I remembered and avoided "binky",lol.
If he is not crying for the binky, then the obvious question is why is he crying? Crying is just a "symptom", what is the real "sore". Once you know the answer to that question, you will be able to implement strategies to relieve him of whatever it is that drives him to tears. If in fact it is the binky or lack of the binky, I wouldn't return it, 2.5 years is probably well past time for him to ditch binky, broken or not, right?
If you don't mind incentive-based behavior training, including frequent preparatory conversations regarding the upcoming bed time, perhaps you can offer him to do something special and fun in the event he lays down and naps quietly. For example, remind him early and often about the pending nap hour or bedtime; tell him what a big boy he is and how big boys like him take their naps without a binky and without crying and when they do, their mommy's have special surprises or adventures waiting for them. At 2.5 years old, "special surprises" can be nearly anything: finger painting, putting stickers on paper, riding their trikes, "swimming" in a bubble-filled tub, etc...
Again, I didn't have the "binky" issue...mine was getting her out of my bed! Maybe this will help get your creative juices flowing. P.S. I am pleased to announce that my neice is now 12 and doing just great! Hasn't mentioned "binky" in at leat 10 years ;-)
Good Luck!