And the amount you can collect is limited by section 14.2 of their Master Subscription Agreement to the amount paid to them in the last 12 months. [0] To get more you would have to show they committed fraud or were grossly negligent, which could then invalidate the contract. IANAL but this stuff is pretty standard.
[0] https://www.zendesk.com/company/agreements-and-terms/master-...