453 battery,rear tires gone at 21kmiles and brake pad

Hello ligths fliker ,dealer did batery test ,bad, replace the battery in guarrantee,only lasted 2 years.
rear original tires gone at 21 k miles,tire rack is back order discontinue this tire?
front brakes at less than 10 % at 21k miles ,got the pads fromm dealer over $100 for the set ,and then replace them without changing and toching the rotors.
Rockauto for 3 or more months no stock on brake parts ,we will have to order parts from uk or germany bur ebay makes them send the items and is a 60+ dollars for shipping, they want us to get rid of the cars.