I keep ignoring calls from my former employers lawyers

who want me to come in and talk with them about a lawsuit where my former employer is getting sued by a customer I was the salesman for. I left before the catastrophe happened. I didn't design it, estimate it, order the materials, managed the installation, or inspected it with the manufacturer, nothing other than sold it.

Several months ago one of their young lawyers called me asking for "help" with some questions. He wanted me to tell them which county most of my former employers employees lived in. Which was an immediate red flag for me. So I asked why would you call a former salesman that's been gone for almost two years to ask where most of the employees live? Why wouldn't you just ask management/ownership that instead of me? He said they were looking for a change of venue from one county to another and needed my help. I said no frickin way I'm going to tell you a factual statement because I don't know, ask the owner. He also wanted me to tell him what county I was in when the contract was signed. How the hell can I know where I was when the contract was signed when it wasn't signed in front of me and it was probably three years ago by now? I said I can't help you.

Fast forward to now and these fricks won't stop calling, texting, and emailing me. They say "we received notice to get your statement/deposition".

What should I expect? Subpoena? Should I hire a lawyer? Anybody been in this situation before?