My two cents...

The TSA management structure has no vested interest in the quality of service at a particular airport - but the airport manager and local airport commissioners (often business people) certainly do.

I think who you call depends on the seriousness of the issue. So, this would be my escalation path...how high you ultimately go would depend on the issue affecting you.

Level 1 - screening supervisor
Level 2 - screening manager
Level 3 - GSC - the airline 'ground security coordinator'. You can request this person be called from the checkpoint, or if you have a really troublesome TSA crew, you may need to return to the check-in counter to ask for them. If the counter agents refuse, you may need to call for the station manager or duty manager
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That is about as high as you can go for 'on-the-spot' resolution at most airports. From this point on, it's pretty much a letter writing campaign, except at much smaller regional airports where the airport manager's office is local and the person is accessible.
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Level 4 - the airport's manager for security or operations and the TSA FSD (Security Director, aka the TSA's regional manager) - write them both, cc-ing each other
Level 5 - the airport's general manager
Level 6 - the airport commission
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Given that your Congresscritter is 98% likely to reply to a complaint with a hollow 'anything for security' form-letter and the FAA's local office will just defer any complaints regarding security to the TSA, once you've hit Level 6, that's probably as high as you're going to get with people who are both empowered AND stakeholders in the performance and reputation of customer service delivery at the airport.

Also remember that money talks - if there is an alternate airport nearby, take a few trips to it and send copies of your receipts (and those of family, colleagues, etc.) to the airport manager the airport commission to show you are avoiding the problem airport until the issue is resolved.

Beyond that, you're last option is probably the media...