Glossary:
bill - /bɪl/
noun - a request for payment of money owed, or the piece of paper on which it is written.
frustration - /frʌsˈtreɪ.ʃən/
noun - the feeling of being annoyed or less confident because you cannot achieve what you want, or something that makes you feel like this.
refund - /ˈriː.fʌnd/
noun - an amount of money that is given back to you, especially because you are not happy with a product or service that you have bought.
willing - /ˈwɪl.ɪŋ/
adjective - to be happy to do something if it is needed.
keep track - /kiːp træk/
idiom - to make certain that you know what is happening or has happened to someone or something.