I had a personal home-tuition teacher who used to coach me since I was in 9th grade.
At first, he was a very sincere teacher, who always gave me sufficient homework, gave me extra practise questions, and generally helped me do better at his subject (Mathematics). In return, I tried to be a sincere student, and did all the homework he gave me :), and also tried to give him the study material that he asked me for, as I had a lot of extra study material lying at home. My teacher would see these, and he would ask me for a copy of those. I would (or rather, my parents would) take a copy of them, and pay for the copies themselves, as there is a tradition in India that the teacher is to be respected even more than God himself (see here).
As time passed, my teacher stopped helping out so much, and began increasing his fees while delivering lower quality of teaching. He even began asking me (again, my parents in reality) for payment even for the extra material that he used to provide me with.
In course of time, I wrote and qualified for the second stage of a certain examination, which I did partially with this teacher's support, and partially with support from my school. However, a few days before the actual examination, my tuition teacher said that he had gone abroad for a business trip, when in reality, he had gone for a holiday with his entire family. I got to know this from a really reliable source. This really made me furious, because I had multiple doubts to ask, and at that time even my school was closed for the same holiday (Dusshera and Diwali, if anyone wants to know).
Then, when I was preparing for the second stage examination, which happens a few months later, this teacher began providing me with substandard quality of questions as my parents had made a delay in making the payment. Nevertheless, I continued to help him, and one day, he asked me for some really good and expensive study material, for a "few" days. He took the actual books this time, not a copy, and he hasn't returned it yet. It's been nearly a year now.
Ironically, I actually qualified for the second stage of the examination, even with the poor-quality questions I had prepared with. However, now, I am no longer in contact with this teacher, due to his attitude and high fees.
Should I thank my teacher now that I have qualified? If yes, then should I ask him for my study material?
I'm a teenager from India, studying in the 11th grade now.