Defective Battery

I bought a 619 Willard battery at Midas Hillfox December 2014 as my old Sabat in my Nissan Xtrail gave in after good years of service purchasing the vehicle with that Sabat battery...Being a Willard fan I bought apparently \The Best"battery for the vehicle when I traded my old one in at Midas Hillfox...In May the battery stopped holding it's charge and I've had to kick start and jump the battery up to this day!!! If the Xtrail stands for 2 days the battery dies....Midas sent it off for a good charge last week for the whole week and upon return and inspection I was told that the battery is good but still only lasted 2 days....I was now told it could be my tracker unit yet I removed the battery from the Xtrail and placed it in my VW Fox which basically has no electronics and it lasted 2 days there as well???? I have been stuck where ever I go with battery problems ever since the purchase of that weak battery....Now they wanna send the battery in again or test my vehicle to see the charge??? Vehicles were meant to drive powered by batteries and not stand for weeks on end while someone figures out what's wrong with an obvious defective battery!! I'll buy another Sabat thanks!!"""