I’m helping older relatives and they suspect a scam. When I called it rang unanswered. There is no county listed. I used an AI eraser on my phone to erase the address and truncate the owner number. Thanks for any help with this… I hate to waste time on this type of thing.
100000000% SCAM !! …. Throw that in the trash and never think about it again 
Absolutely not a scam. Plains Marketing, a well known purchaser, as well as other purchasers have large sums of money in suspense due to a) owners who have died and the heirs haven’t done title work, b) they took over from another purchaser, c) the owner moved or d) internal errors such as somebody misplacing the address.
Answer the letter. Lets assume its a big scam, which it is not, you’re disclosing your name and address. Oh, my, how they will cheat you regarding that.
I have a client who was contacted by an operator who had lost track of them. They had $800,000 in suspense. Now, your relative’s interest is not going to be that large. Now, if the relative doesn’t answer, the money will be thrown into the unclaimed property fund. They can retrieve it from there. But, that is a major hassle compared to just telling Plains that the relative is alive and well.
Tim is absolutely correct. The mailing address matches the Plains website. Sometimes an account also goes into suspense because the USPS mistakenly returns a letter as undeliverable. This is why it is important to follow up when royalty payments stop without any notice. Help your relatives get organized by gathering up all documents about the minerals, wells, division orders, leases, check detail, etc into file folders and also scan. This will benefit ultimate heirs. When the Plains check and detail arrives, identify the well(s) and opeator(s), and ask if Plains will continue to pay the royalties. If not, you will need to contact the operators to get into pay for the future.