We've been friends with a couple for decades. The female of the couple has always bought presents for us and the children. This was fine when they were kids. Now the kids are all grown up and in their 20s. She's still doing it and I'm struggling to get through to her that it's really not necessary anymore. We've stopped buying for their kids. Yesterday, she dropped off a bag of presents for the family. It's stuff that she wouldn't dream of eating (think candied jellies, cheap chocolate liqueurs - the stuff of leftover xmas raffle prizes (which is where I strongly suspect they came from as she's a teacher). We'd not eat them either and she knows this.
How do I get her to stop? I've tried saying before 'let's not do presents this year'. She stopped that one time but then resumed the year after. It makes me feel uncomfortable especially as I can't afford to buy for her family now. So, suggested strategies to make her stop?