2021 2500hd denali

I have a new 2021 2500HD Sierra Denali with 300+ miles on it , only owned it for about 5 weeks , its been on the tow truck 3 times because it won't start , it turns over however it won't start. I have gotten messages from on star saying "it's due for and oil change" , "service engine and transmission within 1 day" , "your battery is critically low" of which none of these messages makes any sense with the newness of this truck. I must add that my dealer has been very good with trying to help me out (to keep me smiling) however I'm not at all happy with GM at this point. this is pretty sad and concerning safety wise that a new vehicle such as this (or any for that matter) has this issue right out of the "box".