Complaint about IELTS Prep Class

Gotta earn those diamonds somehow, even if it's by complaining. Feeling frustrated. Long post ahead. I recently had a trial lesson at IDP for IELTS. Maybe they have a lot of students (?), but I couldn't confirm my spot for the trial lesson until the night before. And we agreed on a trial lesson two weeks ago, but it was me who reached out around 6 PM on the day itself, as the consultant didn't contact me as promised. I'm interested in the speaking and writing class. The teacher for the trial lesson mainly lectured and assigned homework, but they wouldn't let me attend a second trial lesson, so I have no idea how the teacher provides feedback. (From past experience with another institution, the teacher's feedback on essays felt like a game of 'spot the difference,' just pointing out where my writing deviated from a template without explanation. Honestly, a part-timer could do that...) There were other random incidents with different consultants in between. On the day of the trial lesson, there was no one at the counter. Then, the Mid-Autumn Festival holiday came up. Today, after the holiday, is when my next class would be. I contacted them via Line to ask if I could have a second trial lesson, and they confirmed it was possible. I asked them to print a payment slip, but they said they needed to explain something to me – that the fee for the second trial lesson couldn't be deducted from the official tuition. I said it was fine, I still wanted to try the second lesson. Then, they immediately said the teacher had decided to take a leave of absence today, so they rescheduled my trial lesson for Thursday. Since I knew they had rotating classes, I asked if Thursday's lesson would cover the same content as today's. They replied that Thursday would start a new unit. When I asked what would happen with the content the teacher didn't finish last time, they flat-out said they don't offer second trial lessons. They had already printed the payment slip. (To be continued)