OneDrive deleted eveything on my computer

Im reaching out because I'm going through a very diffucult time after onedrive deleted almost everything on my computer. I had never given OneDrive permission to Access or sync my entire sysstem. Still, it somehow deleted crucial personal data including system files, document, reports and apps.

I puchased a 100GB OneDrive storage plan to upload files from my Samsung Gallery, and i successfully completed that process. Later, when i opened my computer it kept asking me to delete around 740 files. I didnt understand what was happening, so i didnt delete anything for a while. Then i saw a message saying my storage was at 1750% capacity and i had no choice but to click delete button. It even asked are you sure you want to permanently delete these files, and i confirmed. Cause i thought its gonna delete unimportant files.

Shortly after, when i checked my phone again i realized my 100GB plan was gone and replaces by a 5GB plan. Thats why its saying saying my storage was at 1750% capacity. I checked the OneDrive deletion history and as expected, it was empty my partner and i tried to recover things but nothing worked.

Why was my 100GB plan downgranded without my knowledge or permission?

Why did OneDrive permanently delete my items, even thought I believed it was a backup platform? Why did it opload and sync nearly everything on my PC without asking for my consent in the first place.

I really hope you can help me recover my data. Ive lost extremely important personal files because of this.