I'm Being Blamed For My Manager's Mistake

My real question first: Is this worth getting a lawyer involved at this point?

I haul fuel in a commercial vehicle. I started working out of a new yard two weeks ago. Three days ago, I text my director supervisor asking her what account to purchase a load of fuel from to take a station I was delivering to. Accounts can change very quickly because we try to stick with the supplier that is the cheapest. I was given an account number, I fueled up using that account number and delivered the load. The next morning, I get a long message from that manager saying I had delivered the wrong fuel. It was very accusatory that I had made this mistake and then I was put on suspension without pay. Today, a day after Christmas, I have HR reaching out for a conversation. They are doing a full investigation. The problem is, the words they are using in this message to have a phone call still makes it seem like they feel I'm at fault. I am nervous to call them back because I'm stuck between a rock and a hard place. They'll either try to blame me, although I have the messages to show differently, or I will be the new employee who got a seasoned manager in trouble. Is this the time to get a lawyer involved or should I wait?