Paying Predial in Person

Very interesting thread.
The previous two years we paid predial cash on site. Last year was a little painful ( it took the administration long to aknowledge our new Fideicomiso). If I could avoid it I would. I have questions :
1) What is the alternate solution to "in Person" ?
2) Has anybody paid with a Canadian credit card ?
3) Do you know if the office is open on Saturday ?
Thank you for sharing your infinite knowledge .