i have tried to report 90 days online, by mail and in person, however i resorted to report in person as i could not get immediate response that my report is accepted by immigration or not, using the other means, this changed since the thai visa centre initiated and extended the service to report 90 days for all interested foreign residents, at 500 baht per report, and discount if use them for more than two consecutive reports, i trust visa centre's service that they will do it in very professional manner and indeed they are, once set up and registered with them, i was able to know online the progress and the 90 day report issued by immigration is delivered to me by registered mail, i am very satisfied with their service and would recommend you seek their help for 90 day reporting or other matters as necessary