Check frequently.
Hi,
I know u'r situation.Because I was also in the same situation like u for the past 1 month.My problem was i got appt date for my mother in june and my father did'nt have passport so he got on july. Then i had to chenge everything to apply my parents together,but i got a date on july when i cancelled both.Then i tried a lot .I got so many dates after that.Now i got a date in june.Try frequently.If u try in the morning 9 and u did'nt see any availability,then don't try at the same time.Try afternoon or something like that.They open the slots in different times in different days.And remember if u are getting a date in july and u need a date in june,click the availability in july.Because then only they will show slots in june.But i don't know what is the trick behind this,maybe priority.I have this experience.Try to check frequently.
All the best,
Sree