Read The Fine Manual and quote it to them. It states how to record OTA. And Scott has a thread posted here on it. Keep calling, quote the manual, send an email to ceo if necessary.
I've had the same problem with appearing/dissappearing timers. I reported the issue to two tech reps who both said they were not aware of the issue.
I'm on my second 622 with the same problem. It ONLY happens with OTA. This is a MAJOR bug and should be fixed ASAP!
Currently, I'm avoiding OTA timers because they weren't firing consistently for me either. From this thread, however, it seems like some people are not having the problem...?
There also seem to be multiple posts/threads around the forum discussing this topic. Scott mentioned over on this thread, that folks using the 61.5 sat may have gotten bad EPG data. I would be one of those folks.
I do know for a fact that it's not a PEBCAK error (or perhaps in this case PEBCAR ) because, through experimenting, I've eliminated "priority" and other multiple tuner type scheduling problems. I miss my 942 in this regard, it had no problems with OTA timers and I really prefer OTA SD to the SD on HD LiL's.