Needed two new SIMs in six weeks: is it the SIMs or my phone?

I have a Sony Xperia Z3 Compact that in the beginning was a bit problematic:

Firstly, on day #9 of ownership the phone died could not be revived. Spent about two months at the Sony Service Center.

Secondly, about a year later, I noticed the entire phone had warped, so much so that I couldn't use the magnetic charging part with a case on the phone. So, another month at the Sony Service center.

Now, in the past 1.5 months, I lost the ability to send/receive phone calls. Both times, went to the True shop and they replaced the SIM which solved the problem.

Is it more likely that the SIMs I had were the problem, or that there is yet another (or the same?) problem with the phone itself?