You relied on the representation of the other party that they agreed to X(written contract or not, written is easier to rove, but not essential), and then took actions based on the expectation of X.

Costs might include hard materials & labor costs for preparing the site, your labor in preparing the site, lost income for time you spent, opportunity costs of not taking advantage of other opportunities (e.g., how much electricity costs you incurred by not putting in other panels instead of their contract), and emotional distress.

The problem is going to be proving each and every one of those charges in court, in the face of both legitimate and bullsh*t arguments by Tesla's lawyers - and they will bring both types of arguments by the truckload.

What Tesla is counting on is that it will almost always cost more to pursue the lawsuit than you will recover, so no one will step up and sue. They have scale, you don't.

This is why class action lawsuits exist - so that all similarly situated plaintiffs can combine their actions into one, and pursue it with one firm. It would not surprise me that someone at a class-action firm is already examining these reports, taking notes, and making calls. Similarly, anyone with this problem should be contacting class action firms this morning.

As mentioned in the article, at least one individual spent thousands in preparation for his roof.

The time and effort of getting the initial work done and now the revelation of a double digit percent price increase, and a low key threat of further delays unless you sign right now?

Sounds quite distressful.

In fact, it is by design stressful, so as to pressure the consumer to accept the new contract.

I.e., a lawsuit is not scaleable as an individual.

Tesla are taking advantage of that advantage of that asymmetry in scale, and basically saying "this is wrong, so sue us", knowing that few or zero will, and most will just eat that dung sandwich.