European Samsung S21+ not taking calls under AT@T network since June
I moved to the US in March and took AT@T as mobile provider. I used my newly bought Samsung S21+ I bought in Europe. Until June all worked fine. Since June I cannot make or take any calls while SMS and Data work.At AT@T they told me that this was due to a system update they did that was supposed to prevent cheap 3G phone to operate under the network, which isn't the case with my phone. They have tried to reset , change Sim but without success. Any ideas what I can do? What is unacceptable by ATT is while this issue is 100٪ caused by them they don't allow me to trade in my phone and get a phone that works..even the same model. Samsung USA also poor service not helping or offering a replacement phone.