I changed the battery, calibrated: but it only worked for one day!

If you calibrated the battery, then we can say the charging circuit worked. I just mentioned this on another question (iPhone 6s battery replaced now dead) I'll repeat it again:

We have been seeing a large number of battery complaints on this forum of late. My suspicion is that with the huge, worldwide demand for batteries following Throttle-gate, lot's of really poor quality batteries are making there way through the supply chain that otherwise would not under normal demand.

I have even noticed a large number of complaints regarding iFixit batteries, which are normally a gold standard as far as battery supplier goes. That's just my humble opinion though :>).