HELP!!! Trying to reschedule test thats in 2 days but website wont let me

My test date is 6/15 and I've decided I should probably move my test back 10 days. I tried to reschedule on the website but it is not letting me and is giving me an error. I tried to call but the voicemail stated theyre closed. Trying not to freak out right now--what should I do??