Where do I pay tolls in person?

We moved here 1st of October to be exact and had to use the toll ways from Cypress to Downtown a couple of times. I've been checking HCTRA website and it says it could take up to 30 days for out-of-state license plate transactions to post. It's almost a month and a half and still nothing shows up I don't want to get penalty. I actually now have a TX license plate and the EZ tag (ordered online). Is there a way I can pay voluntarily in person? And where? Thanks