Where does my responsibility end, between the company and the customer?

You stand where two forces meet — the company behind you, the customer in front of you — and both push. When something breaks, both look at you. This is the job. But notice: you have quietly started answering for things you never agreed to answer for. Strip away the flattering story that you can fix everyone's dissatisfaction. You cannot control the policy you didn't write. You cannot control whether a stranger's anger is really about you or about a bad day, a bad system, a bad week. You can control what you say, how you say it, and whether you tell your team the truth about what happened. Do this with others, not alone. A team that names its real limits together stops absorbing blame separately, in silence, at night. That is the actual work here — not becoming unbothered, but becoming accurate about what is yours.