I have reservations for 8:30 but won't get there untill ten. They are not answering phones. Do you think they will still let us in?

Yes I was a little bit late too and it was no big deal

I just went to this zoo on Sunday, March 28, 2021 and had a 1030 reservation. I showed up almost 30 mins late but had no problem at all getting in. Looks like u can also just buy tickets there so the whole need of slotted times seems redundant and unnecessary...was extremely busy

I don't believe the park is open that late, but I do hope that I'm wrong.

I believe you have 30 minutes from your reservation time to enter the park. They might not let you in.