Sabat battery issues bought from Midas

I had a Bad experience with Midas regarding Sabat battery. Bought a battery last year April and for the past 3 weeks it started dying on me and yes I took it back to Midas,thinking that it is still under warranty they will exchange. OK they explained that it needs to be tested the charged it and tested it and OK I collected since they can't change when it says passed. I went to Joburg did not use it the next morning it started the car cool went to work. When I was at work during the day I started the car it almost did not start but it did trying to avoid embarrassment of asking for a push. Later I started and it was fine on my way I was asked to go buy food cool went to Romans Pizza waited for my order when I got my order had to leave my battery cant start the car had to be pushed by strangers mind you I drove about 30km from work but it dies. So I would like to know what do I do the machine says the battery is fine but it can't start the car. From Romans I drive about 3ks to home and I decided since the guy at midas said there is something draining my battery I disconnected the terminal the whole night in the morning it cranked for seconds and died. I bought Sabat and I have used it for years on my car never experienced this.