No sim no service

Keep getting no sim no service then Mobile data is turned off. Then it all works again like it should,  then the no sim no service. I've called twice on this issue and the all want the same thing,  it's never fixed. I just recently had this problem. Friday 4/19/2024 and then again Monday 4/22/24 and on Tuesday.  I never had a problem with this phone and I have the Samsung Galaxy S23 Ultra that I bought out right. So it's not the phone it's self. This issue needs to be fixed.