Sources

1. https://blog.hubspot.com/service/customer-relations
2. https://blog.hubspot.com/service/customer-retention?hubs_content=blog.hubspot.com%2Fservice%2Fcustomer-relations&hubs_content-cta=customer%20retention
3. modified chatGPT generated text https://chat.openai.com/
4. https://www.salesforce.com/eu/learning-centre/customer-service/customer-retention/
5. https://www.zendesk.com/blog/customer-complaints-10-tips-manage-better/
6. online activities created by https://wordwall.net/
7. https://www.linguahouse.com/esl-lesson-plans/business-english/complaining-and-apologizing/audioplayer/complaining-and-apologizing-ex2
8. https://www.bbc.co.uk/sounds/play/b01n6sjz
9. https://www.bbc.co.uk/sounds/play/b04bsylz
10. The SERVICE in Customer Service | Simon Sinek
11. https://www.linguahouse.com/esl-lesson-plans/business-english/complaining-and-apologizing
12. https://www.linguahouse.com/esl-lesson-plans/business-english/is-the-customer-king
13. https://dictionary.cambridge.org/
14. https://financial-dictionary.thefreedictionary.com/
15. https://www.macmillandictionary.com/
16. https://www.oxfordlearnersdictionaries.com/
17. picture 1 https://globalpartnerstraining.com/wp-content/uploads/2018/09/L-and-D-Professional.png
18. picture 2 https://www.pngkey.com/png/full/83-839896_customer-feedback-do-ac-logo.png