The girl who likes me suddenly won't let me call her or send a message (I like this girl too), saying that unless she calls me or sends a message.

First: family factors, you are a student, and you are afraid that your family will know. Parents are basically not worried about the loss of their sons when they fall in love with boys, but the parents of girls are worried that their daughters will suffer even a little loss every day! ~ She may be on the safe side! ~

Second: She is playing two-faced. I don't know your occupation, and I don't know that girl's personality, but many girls do this when they play two-faced!

Third, if you are not a student, it may be because of the industry problems she is engaged in, such as some busy occupations such as clerks, or ... I just guess, there is no evidence!

Please explain your occupation, girl's personality and so on in detail next time you ask questions!