Well, that's why I asked. I agree an e-card is not enough for a normal mother-child relationship.
My dh does not have a warm, loving relationship with his mother but I wouldn't call it toxic exactly either. He calls her on Mother's Day 100% out of obligation. He called this last Mother's Day and got voicemail. He left a nice message. His phone was nearby in case she called back. She called several days later and said she had just gotten his message and felt a little "cheated" out of her Mother's Day call. Apparently, he should have kept trying? This is when things stop being gifts and start feeling like work, when they are not appreciated as the gifts that they are. I know that if this happens over time, it tends to make people want to do less and less. (By the way we also sent her a small gift in addition to the phone call). I don't blame the mother in the OP for being a little hurt, assuming no toxicity, but the best way to make sure you don't get much in the future is to not thank the giver for the gift that they DID give. I think she should have thanked the OP sincerely for the thoughtful card, instead of saying it "didn't count". When someone appreciates what I give them, I am more inclined in the future to give even more.
This past Mother's Day I actually spent time with my youngish children explaining to them that once they had wives and young children, the Mother's Day focus should shift to their wives who are doing the "in the trenches" work of mothering young children. I told them I'd be happy to hear from them but their real job at that point is honoring the mothers who still have young ones and probably don't get much of a break.
I don't get it when people who haven't had young children to care for in years expect the day to be ALL about them. A card, phone call, yes all appropriate assuming no toxicity. But most of the day should be spent, in my opinion, honoring mothers with children still in the home. Just my opinion I know, and getting slightly off topic.