Auto stop start not working

Purchased a new to me 2020 Blazer RS recently. Love it but noticed the auto stop start did not work. Not a big deal to me but thought hey its under warranty for a month so took it in. Here I am on day 3 and they have no clue. Finally gm tech support told them to run a load test on the battery. Hmm...im not a mechanic but thats what comes up on Google searches..and, the battery failed. Ok they will install the battery but need it the third day because they can't get a battery installed in 3.5 hours. I think the dealer is messing with me...