Hello @Mounir Bsaibes
Sorry for your experience. Recently, Lanugage understanding and QnA maker are rebranded to Language Service, and LUIS/ QnA maker become a feature under it called Question Answering.I have created a request to content team to update the name and make everything connsistent(Some of the doc from Bot Service side are not updated well, I am sorry for that). Although the rebranding happened, the QnA maker/ Knowledgebase/ LUIS are still workable, you can use all of them.
If you are just starting, I would highly reccomend you starting from Language Service.
This is the quickstart I will recommend you to refer to: https://learn.microsoft.com/en-us/azure/cognitive-services/language-service/question-answering/tutorials/bot-service
This is the latest learning session which may help you - https://learn.microsoft.com/en-us/learn/modules/build-faq-chatbot-qna-maker-azure-bot-service/
I hope this helps.
Regards,
Yutong
-Please kindly accept the answer if you feel helpful, thanks for supporting the community,