Disappearing notifications

Hi, I recently bought op12 and was amazed but yesterday I noticed my notifications are disappearing, and that's something I will not accept. I did some research and found that it's known issue and company know it but I didn't found any solution to that. Do you have any working solutions to fix that issue ? If not I'm selling it right away. I owned iphones, Samsungs, knowing that Chinese Xiaomis etc have software issues but hearing that OP have such great reviews and great system I wanted to give it a try and I'm so disappointed..