Anyone know of a medical imaging center that mails your bill?

When I’ve had medical imaging done before out of state they’ve always sent me my bill with my copay after the service. But recently I contacted a couple hospital affiliated imaging centers in network with my insurance who told me copay is due at time of service. I’ve met my deductible this year but need several different tests so I would rather pay over time. I plan to call around but if anyone has used a company before in Houston with this payment model they could recommend that would be helpful thank you!