I have been a customer of Chevron Texaco products forever until: I received a recent billing indicating a late payment charge on a payment that had been mailed at least three days before the due date---and due to either the US Mails or Chev-Tex, was not received until two days after the due date.
The late payment charge was not the amount that the terms of service agreement provided, but five times more. In addition, I was charged interest on the amount supposedly paid late.
Chev-Tex accounting agreed to give me a credit for the late charge, recognizing that its late receipt was not my fault. However, it demanded that I pay the full amount, including the late charge and interest, and it would credit the late charge on a later billing. The interest, it said, "can never be credited"---even though there was, by its admission, no late payment.
Chev-Tex must be encountering financial problems because it has started charging a "report delivery" fee for its bill (!), it has shortened the time to pay, and it engages in illegal billing practices.
I got no relief from Chev-Tex. So, it has lost a customer of its products forever. It will have to hold the credit to which I am admittedly entitled forever, since I will not buy its products again.