Retentions asking for a one-time passcode?

My coworker gave me the phone number for retentions - (800) 972 5757. I was calling to lower my bill, and when I called they seemed to cooperate quickly. They asked for confirmation of my name, address, and phone number. I provided them with all three (which I am now regretting...). What weirded me out is they asked me for a one-time passcode they were sending to access my account.

When he asked for this I hung up... It's very strange to me that optimum wouldn't have access to my account on a back end to lower the price. Was this really just harmless, or was I right not to give them the code?

Thank you guys! I get paranoid about these things, lol, and I'd rather be safe than sorry.