Eztag toll in rental car and website down for maintenance

Hi

We are visiting from London. We drove today from the Houston Space Center to San Antonio and went through many Eztag tolls and the Sam Houston toll. Only realised after we had gone through one so we kept on going assuming we'd be able to pay later.

Now it seems like the HCTRA website is down for maintenance. Given it's a rental, I want to avoid and extra penalties if the fine makes it's way to the car company much later. what's my best course of action to pay the toll?

TIA