- just swear at the first agent.
At the ISP I used to work for, some years ago, swearing would have the agent pressing a button on the phone. This would save the recording of the call for later review by the owner of the company. Depending on what you would have said you'd get a letter warning you not to swear at the staff, a letter terminating your service, or, in the worst case, the owner would take the recording to the police-station and file a complaint against you. About half those complaints resulted in suspended sentences and hefty fines.
The average call center agent 'survives' the first line a few weeks before burning down. He averaged three years for his call center staff.