I bought an echo dot at best buy for my Mom. She can't get it to work and Amazon said because she did not buy it from Amazon they can not help her. If she brings it into best buy can they help her with returning it or making it work?

You purchased it at Best Buy, so take your receipt with you. Explain that it was a gift for your mom.Ask them to have one of their service reps show you how to use it. Once s/he does, teach your mom. If it doesn't work, trade it in for one that does.

The folks at the local Best Buy are really good at helping me after a sale. Bring it in and they will take care of you.

I'm pretty sure they will help in some way. Bring your receipt.