The problem contacting large organisations is the time listening to multi recorded messages at your expense to speak to a real person, who when you explain the problem can't or don't comprehend the problem and if you want something done or give instructions etc. don't carry them out. This then involes going throught the whole rigmarole again with no guarantee it will be solved. Also with premium numbers the businness is making a profit at your expense.
OnePlus 5 review