There is a similar problem with chain text messages. Last year, a friend asked me to send out a tehillim text for his grandmother, she was very sick. I realized that there was a problem when I received the same text 2 MONTHS later.
There is another problem. If people get many of these text messages asking for tehilim to be said, and they don’t say tehilim, then their sensitivity gets lowered majorly.
I asked a prominent rav what the solution is. He said that I should ask the people on my “texting list” if they would like to receive these tehilim texts. If they say yes, then continue sending them because they will say tehilim.
A possible solution to both of these issues (texts and emails) is to verify your info before sending it and you should put the date on the text so if someone receives a text asking to say tehilim and its dated from a month ago, they will know to disregard it.