Realistically, if it comes up in a background check, tell the employer it was expunged and legally can't be counted for any purpose. Then find out what background checking service they use and get them to expunge it or threaten to sue them. If the employer refuses, tell them you will sue them and the unnamed john doe and they will be forced to provide the information after spending lots of money including paying your attorney fees and costs.

You need to get a copy of your NCIC record from the FBI. Go online or call them for the procedure. You need to get it removed there first. They do not remove anything unless they are directly asked to or ordered to do so by a federal judge. They can ignore state courts with impunity.

I have never heard of any such service as you are looking for.