Can I use an old retainer from middle school / how does Marily bridge affect making a new one

I have a “zero bite” which means my front teeth just almost cover/occlude my bottom front teeth. Braces and retainer lessened this to where my front teeth hit at about the halfway mark of my bottom teeth which is how they’re supposed to.  But I haven’t worn it for years because my orthodontist had told me it was optional if I had to wear it or not, he didn’t make me understand it would keep on reversing back if I didn’t. Sigh so I'm 26 now and my bite is back to what it was. I got a Marilyn bridge put on my two bottom front teeth so my old bottom retainer definitely cannot fit. Is it possible to make a retainer molder for teeth with a Marilyn bridge? Would it hurt the bridge? Because I don't see hwo the cite could be fixed with only a retainer for the top teeth, correct? Anyway, my major question is, is it possible for them to make my old top retainer fit my mouth again so I don’t have to buy a new one? In the sad event I have to purchase a new one, is it common for them to include replacement retainers in the price, in case it breaks for whatever reason? I live in North Carolina if that helps. Also how often would it need to be tuned and for how long, would you estimate, in order to fix the bite issue? On average how much is each retainer tuning appointment? Do you think it is possible to learn how to adjust the retainer wire myself, to save on this adjustment cost?