How to change the text of the buttons, acknowledgement strings etc?
If your site is multilingual, please follow the below procedure:
Use POEDIT softeware to edit the language files and to prevent from overriding when you made an update, you can copy languages folder to yourtheme/dvin-wcql/ folder(create the folder if not exists). Below link might help in how you do it with POEDIT:
If not multilingual, you can use the filters mentioned in this FAQs.