Windows Authorization Failure after repair - Failed CS

I am so at my wits end. I sent my daughters latop in for a physical repair (screen mount broke and bottom case cover cracked) and it came back repaired but unbeknownst to me (because 99% of what she does on it is web based) the hard drive was wiped, she now no longer has office (which I can fix) but more importantly windows will not activate. It says it is not a valid copy and to purchase one. I spent over an hour on hold to be told there is no way it was related to the repair and that they couldn't help me and to call back. Then I was told via whats app that someone would call me (they didnt) and then given another number and I spent close to two hours on the phone with them only to be told they couldn't do anything (I cant install chrome so that the remote access works because I cant get out of S mode because windows isn't activated) and was told someone would call me today between 9:30-10:30. This also hasn't happened. I tried going through Microsoft and looked up the series of numbers using the slui 4 command and that also didnt work and they suggested to send it back to Dell. I just need it to work and I need someone who has the appropriate authorization to make it work fully. HELP PLEASE!