The card, which had "thinking of you" written on the front, had the message: "Stop begging for money!
"Enough is enough, with raffles, just funding.
"Why do you still want people giving money to you?
"What will happen to the money when there is no cure for you?"
It is not known who sent her the letter, however Land is worried it is somebody she knows as it didn't come with a stamp.
"I was just shocked that someone would do that to somebody in my position," she told Lincolnshire Live.
"I don't understand how someone can be so bothered about my life that they go to the effort to do something like that.
"I'm not angry, I would have liked to have discussed the issue with them. I think I'm inclined to say that they're more to be pitied."
Land said she wanted to remain positive and not let he card put her down.
"I don't want this to take over the times I am supposed to be enjoying," she said
"I always wake up in the mornings feeling upbeat with a smile on my face. I guess I did get a bit complacent when I beat cancer the first time around, but I'm willing to go the full length to get rid of this."
On her crowdfunding page, Land explains the treatment she is going through and reveals why she created the account.
"As I have not got a lot of time left I am desperate to raise these funds so I can have this treatment which if works could give me extra precious time with my children," she wrote.
"My youngest children are just 7 and 9 and I am prepared to do anything to make sure I am around for them as long as I possibly can be."
You can donate to Land's Justgiving page here.
