Help I've lost all my Appointments! - Urgent!

Hi

I upgraded to Appointments 1.91 but my site stopped working as I'm running some custom security code which was conflicting.

I then tried to downgrade back to 1.90 and ALL my appoinments have dissappeared!

Support is enabled! This is a disaster please help! I'm going to get my Server provider to install a back up of my site but I dont know how long this will take.

Kind Regards
Kieran