[mothered]

According to what Microsoft tells me, everything should be resolved today, and they should confirm that they are giving me the refund.

Regarding TNF and DNA, UPS confirms that the investigation is complete, but that they cannot send me any data, that I have to ask TNF for it. These, for their part, say that UPS has not sent them any information... It doesn't seem like they even want to collaborate, tomorrow I'll try again and if there's no result I'll have to start considering hiring a lawyer or doing the chargeback

If UPS fails to provide details of their Investigation, you have a very strong case to successfully hit a chargeback.