(In my current knowledge) I try to answer...
Where is the focus of the conversation?
"have -ed" stands for
1 "at the time of finishing something".
2 "something suceeds from the past time".
3 "have experience of doing it".
B:The text I sent you yesterday afternoon.
and today , A and B meets each other.
you can understand "1" and "2" is not right for this answer.
you image that A has experience of reading B's text.
So, your answer is also right in a sence.
I have been to this park once. ( experience )
I have gone to the park. ( finish ) (and I'm not here now.)
I have studied English for a long time. ( suceeding ) ( I still study English)
B want to ask A the fact "A read B's text or not"
B don't want to ask A's experience "Have you ever read my text?" No.
Certainly, if A read B's text, A says, "I had read your text before you came!"
This is not for checking A's knowledge of B's text.
There is the focus for A's experience of reading it.
as your first thoughts, B even can speak "I have sent you my text".
This means I sent you my text book and the moving has already finished,
so I have an experience of sending you my text book.
I have an experience of sending you my text once.
Is it strange, isn't it?
"Before you started to wait, hadn't you gotten my message?"
your answer sounds that "Do you have an experience of getting my message before you started to wait?"