You can Contact Gmail Help Center customer support at 888-625-2848. The number leads to an operator service that is based at Gmail headquarters in Mountain View, California.
When you dial the number, an automated menu will guide you through a variety of different choices. The majority of the time, the outcome of your call will be a voice recording instructing you to visit whatever website in an effort to remedy your problem. You could occasionally be put in touch with a live customer support agent.
During PST business hours, this service is accessible 24/7. If you call outside of specified times, a voice recording will just guide you through the choices; you won't be able to speak with a real person.