I've used this phone with only minor problems since September 2017. Those have all been worked out.

However, three days ago my mobile data stopped connecting. I cannot get any internet.
I've made sure that my phone is updated:
Current:
BV8000Pro-Blackview-V0.1_20170803_20180307-1950

But I think the new update is the problem. How can I reset my phone to last weeks build?

Hi there! Please perform a factory reset following this tutorial:
http://bbs.blackview.hk/viewtopic.php?f=192&t=334922