Student or Learner
Teacher, I am writing an email. Can you check for errors. Can I use present tense in this situation?
I have just called ABC Adventure Group to enquire if there was a possibility of booking a trip tomorrow and they informed me that there are no available dates and that the next available date they have is next Wednesday.
Your sentence is correct. When you ask about whether you can use the present tense in this situation, I'm assuming you mean not needing to change to "..informed me that there were no available dates...next available date they had..."
The answer is yes, it is appropriate here. You could change it, but you don't need to switch to past tense in reported speech if the information is still valid when you report it.
(not a teacher, just a language lover)