Service center repair in Japan experience

I have a Retina MacBook Pro (model of 2012) which recently started showing several issues. The system would shut down intermittently, the base would get very hot, the display had image sticking problem, sometimes the trackpad would work on its own and the battery was showing 'Replace now'. So, I took it to Apple store, Ginza in Tokyo.

The person serving me offered two repair options. First option was to replace the battery which will come with topcase assembly consisting new battery, keyboard and trackpad. The staff suggested that it probably was the battery which may have expanded and it is now interfering with the trackpad and causing intermittent shutdown. The second option was a repair at their repair centre which for a flat fee will fix all the issues in the MacBook. After thinking about this for a while I finally decided to go for the repair centre deal. I wasn't convinced that the expanded battery would be the cause behind those intermittent shutdowns as I had this issue even when the battery was still good. I took the machine to Apple Store before when I heard about a common video card issue and an extended repair program for this model but they refused to acknowledge the issue. After receiving the machine, it was a very quick job from the repair center and I received the computer back within three working days! When the computer was returned it was looking absolutely brand-new as the topcase and the display was replaced and apart from the logic board inside, almost everything got replaced too. But after returning home I discovered that the computer would still restart now and then. So I called AppleCare and they suggested me to take it back again to the store. I took it back to the store yesterday and the person receiving the machine said they're going to send it back to the repair centre again for them to have a look. He said I likely won't have to pay for this repair but they will let me know.

I think it was a terrible idea to spend 70000 JPY (almost $700) on a 4 year old machine. I was told, the system will be thoroughly tested and all issues will be resolved. They clearly failed to keep up on the promise and I am really regretting my decision. I would really appreciate your thoughts or suggestions on this