MAG3

Has anyone had experience of MAG3 or even their little one having a cannula? Our little one went in this week and two doctors couldn’t insert his cannula, all the pain and discomfort for no reason :-(. We have to have the appointment rebooked. We’ve told them we’ll need guided ultrasound next time but they’re saying we can’t book that in, but I’m adamant I don’t want to go in again without it and them trying to do it again. Any experience shared would be appreciated!