Apollo, I have relatives just like your aunt. It's a guilt trip. You're an adult and have the right to decide which religion you want to participate in. Keep in mind that it can be difficult for people that saw you grow up to now see you as an adult. Don't feel like you have to explain yourself to any them.
I would recommend not avoiding their phone calls. You are letting them control your behavior, albeit unintentionally. You don't have to hold a 3 hour conversation with them. You can end the conversation whenever you want. The thing about being raised a JW is that it takes a while to understand your rights as an adult.
Regarding them making up a card to DF you...they are not suppose to do that but it doesn't mean they wouldn't. But I think you are fine for a while.
Life's a journey and I wish you a successful one,
Shop.