How hard is it to get answers about finding a slot for a 42A20?

I was dropped from my MOS as a 88M20 and put in to my other MOS as a 42A20 but the unit I am in does not have the slots and I get told by both my unit and my Battalion. That there is no slots for me at battalion level and they. have none at Bridge level with the unit I am assign. just try to find a unit that will take me I am going out of my mind and all I want to do is work my mos and retire when I get my letter because I have 20 years and 3 mo I would hold off on the retirement if I can just get to a unit that need a 42A20 ?