Caller: She said she was from citylink, but now I’m not so sure! She wanted me to pay an overdue toll over the phone.

I can’t recall going on a toll road. I first heard from them via text on 25th May and I apparently went on the tollway on 23rd Feb, this seems an awfully long time to wait to contact me about it. The text had no contact number on it and told me to text back “call me” and they’d get in touch. I went on the website and there was a bill on my rego number. It would not let me open it unless I opened an account which you have to pay for. Is this a scam?