Well you shouldn't prank them at all.
You see, there is this nifty little thing called the fair debt collection practices act (fdcpa) and if you are getting collection calls for another party that won't stop, that falls under the tcpa. You should be logging each and every one of those calls and then when you rack up enough violations, you send registered mail asking for payment under the fdcpa or tcpa, which will net you somewhere between 500-1000 per violation. If they don't respond and you want to pursue it yourself in small claims, you could win up to 7500, or 5000 depending on your state.
I've made 5000 this way over the years. Judges love to give money away like that in small claims
Do you research first, then set out a plan to trap the fucks. Googling fdcpa or tcpa will get you everything you need. You don't need to be a lawyer or have a lawyer in small claims (you don't need one in state or federal either, but you best know procedure and what you are doing if you want to be heard in those venues).