Because you aren't open on, nor accepting drop offs on, Sunday, it causes me to have to pay for one more day, from 4:30 Friday to 8:30 a.m on Monday. Is that correct?

I rented from them last year. All they had me do was return it on Sunday and park where the camera is and put the keys in the drop location. But if you told them you wanted to return it on Monday..then yes you are obligated to pay for the Sunday rental weather they are open or not.

I woudl call them, you didnt say anything about saturday.

Yes that is what I dont like about enterprise