How to find a variable in php?

Question

WordPress

Good afternoon.
Please help. There is a Visual Form Builder plugin . I use it on my website. When submitting the form, we get the answer "Your form was successfully submitted. Thank you for contacting us."

In all php files and translation files, I changed to "Your order has been accepted. Our managers will contact you shortly."
But I still get "Your form was successfully submitted. Thank you for contacting us."
Plugin directory tree:

Am I doing something wrong?
DECISION:

Answer 1

look again in javascript
if Ajax processing is in progress, without reloading the page - then most likely, the phrase is hardwired there
and there is still a search for the contents of the files, you can use it to find the phrase