What are the challenges you faced ?

What are the challenges you faced : 1- sometime developers were not accepting the bug then I have to show them in meeting and had to give them demo of bug.
2- sometime I got inconsistent bug, its changing everytime. Then it was very difficult me to show them then I have taken executed the same testcase many times and took the screenshot of all the scenarios and shown them to developers.

3- In the 1^st release when I joined customer was asking very frequently changes.