A friend had this problem. The power company didn't want to do anything because they are responsible for providing residential power, not 3 phase power.
HOwever, he had a trick in the form of a recording voltmeter that logged voltage levels over long periods. He then got hold of the specs that the Public Utilities Commission in his state spec'd for allowable voltage fluctuation.
The power company balked until he pulled out the recorded voltage levels that were recorded using a/the voltmeter PUC of his state mandated. At that point the power company could not argue and simply came out, added another transformer to the section of grid he was on and problem solved.
You can P&M all you want about your psuedo 3 phase and the power company won't care. They only have to supply single phase - you're creating 3 phase and not in a way that the power company will recognize as valid.
Show them that the power that they ARE supplying is bogus and you'll be in a different bargaining position.