Have you sent a certified letter, return receipt requested to Chesapeake in this matter?  My suggestion is to cover all the bases with Chesapeake before you turn to a lawyer for help since those are your only two options.  Provide all the basic information in your letter as to your owner name and number, well name and last royalty payment received, etc.  State that according to the state O&G database, SONRIS, there has been no well work over and that monthly production volumes reported to the state have been consistent from your last payment to the current time.  If you were a working interest or an unleased mineral owner, you would be charged your proportional share of any work done on the well after it was originally completed.  As a royalty owner, you do now owe any of those costs.  If you have a contact at Chesapeake, you can ask for the correct department/person that the letter should be forwarded to and this can be done by email which you should keep as a record of your request.