wiping data

I sent my phone in for screen damage on the 26th of July they send it back 3 weeks later after much delaying. Their reason was the truck broke down and it was the only one they had? Is this Samsung? Horrified after turning on my phone my themes were all deleted my bookmarks were gone they reset my browser, i didn't give them permission to mess around with my personal data and settings. This is absolutely unacceptable behaviour from Samsung staff, I don't see why my software was tampered with when the screen needed repair? I am not sure of what other changes one of Samsung's staff decided to do with my phone as I have not had the time to check.