Valvoline Instant Oil Change [VIOC] review: Ruined transmission

I took my 2015 Ford Fusion that has only 32k miles on it in for an oil change a couple months ago. The technician tried to upsell me on every service they offer whether it was due or not and got visibly frustrated when I declined the 30k transmission service...4 times. I am aware of the configuration under the hood and I only ever trust the dealership with transmission work. I drove the car the half mile back home and didn't think too much on it. The car sits a lot as I drove a company vehicle for work so, 2 weeks later, I go to wash the car prior to a roadtrip. It starts to miss shifts, over-rev and stalled as I entered the car wash. I pushed the vehicle to safety and had it towed to my Ford dealer. They stated that the transmission fluid was empty of all 6.5 quarts and the transmission would need rebuilt or replaced...$7000 to repair. I'm sick to my stomach. Valvoline has not responded to my requests for compensation or even an explanation as to why their technicians would drain a fluid prior to approval, then not refill it to correct their mistake.