iPhone 7 failures

We have been ardent Apple iPhone users and supporters. We stared using the iPhone since the iPhone 4 came on to the marked. Every two years we got 2 new iPhones on our MTN contract. So we upgraded from the 4 to the 4S the 5 the 6 and two years ago to iPhone7. We kept on using the 6 and kept the 7 in storage. I needed another phone for my Mozambique simcard about a year ago and unwrapped my iPhone 7. This I used for about a year with the Moz simcard and I went to Moz about 3weeks on and two weeks off. In September 2019 I had to update the software on the iPhone7. After the update, it refused to switch on. I took it to the iShop to see if it can be fixed. Yes – R7500 to fix it. Really??. So I unwrapped our second iPhone7 and used that with my Moz simcard. I used it about 2 months and then in November2019 the software was updated again. Guess what? After the update there was a white screen and it would not switch off. This means we had a 100% failure rate on our 2 iPhone7’s. Both failures took place just after the software upgrade. The one phone after about a year in service and the other phone after 2 months in service. Coincidence??? Has anyone else had similar experiences with their iPhone 7 models? We are now seriously looking at jumping ship and using other smart phones rather than iPhones after this experience.