Production costs?

Hello friends, I’ve asked this question in another form here, but know a bit more now. I receive royalties from Chk in La Salle County (Van Cleve) since 2012/13. My husband died not long ago. I’m having to fight some dragons. My gas goes to JGC and Stonegate. They now have a organizational group to deal with “problems). Chk oil pays like clock work and without much cost even though the lease says oil and gas cost can be deducted. (I don’t have executive rights so that was beyond my control) My DO says NPMI. It’s a standard lease. I have received checks from the gas peddlers, which for unknown reasons, have at times stopped payments on checks without explanation. I find out from my bank. The checks are seldom replaced, when, there seems to be much confusion and they are lumped with new checks. This is odd to me since some are very small amounts.
Gas cost deductions are appr. 60 to 75 percent. I asked why so excessive and why the returned checks? No explanation. I suggested we do this through attorneys. A very slow liaison land woman working part time called to tell me that due to “good faith efforts” the companies will not charge cost into the future as of August 2021. The September check will adjust and credit also. I asked about the high cost in the past again. She didn’t have time, doesn’t know, will let me know now for 16 months. My squeaky wheel seems to have the no cost future deductions clarified IF they pay. I am puzzled why these companies would now be willing to drop the costs. Huge corporations usually don’t work on “niceties”.
Should I pursue this? Should I just wait to see if their good faith will make a difference in the future? Should I now worry about them changing their mind or keep asking, making some demands about past cost explanations? It’s all Greek to me and I don’t want to throw good money after bad with extensive attorney work. One told me the statute of limitations is four years going back and all that was probably wiped out in the Chk. bankruptcy. How do I bow out gracefully if I want to end this battle? They wear me down every time. We are talking about a $25,000 difference over 10 years maybe and I don’t want to anger the Gods, but on the other hand, I don’t trust their accounting into the future.
Any advice would be appreciated. Thank you Evelyn