First:
This has nothing to do with Toyota itself. That oil / tire rotation package was sold by the dealership. Those types of packages (other than the Toyota-branded extended warranty) are not offered by or backed by Toyota- but the dealership you purchased the car from. My guess is that the paperwork that you signed had a disclaimed that said that the package was either non-transferable or non-refundable. It never hurts to check though- look at the paperwork you signed and see what it says.
Second:
Did your 2019 Avalon come with Toyotacare? If so- why would you be tempted to buy an oil change / tire rotation "package"? Basic maintenance was covered for two years or 25,000 miles... so unless that 'package' was dirt cheap, I don't see the reasoning with pre-paying for it when you buy a vehicle. I don't pay my internet provider for the internet service that I'll need two years from now... I'm not sure why someone would pay for oil changes that they won't use for several years.
Third:
How much are you out? My Toyota dealership charges $70 for an oil change and $20 for a tire rotation. So if your dealership has similar pricing- that would mean that you didn't get to cash in on two oil changes ($140) and two tire rotations ($40)... so you'd be out $180.
While $180 is certainly not a small amount, in the context of buying a 2019 Avalon (roughly $38,000-$43,000), that's a pretty small amount. I'd probably be more upset at the "service fee" that your dealership likely demanded that you pay when you bought the new car... because that fee was probably a lot more than $180. (Dealers in my neck of the woods charge $399- and every dealership in the area charges it- as its something that is pushed by the local dealership association)
Perhaps double-check your purchase contract of that 2019 Avalon and see what it says about refunds or transfers... otherwise it seems like this might be a learning moment- not to purchase prepaid maintenance if you aren't going to keep the vehicle long enough to take advantage. Reason #3,023 of why all of the stuff that the finance manager tries to sell you is a ripoff. If there isn't some sort of prorated refund or clause that allows you to get your money back if you sell the vehicle or it's totaled in an accident- skip it.