Same issues coming back

I am a customer for almost 4 years now, but in the last 12 months I have issue after issue with them. And then when it is finally resolved after weeks, the issues come back a few months later. Last week I was without internet continuously for 12 hours. Now again an entire night without internet. This is unacceptable. Seriously considering to change ISP if this issue isn't sorted out soon, and for good this time.