Arkel makes 2 absolutely bombproof handlebar bags. A smaller one and a larger one. I have the smaller one and I love it. Arkel bags are indestructable.
I looked at the Ortlieb handlebag bag before I bought the Arkel. The Arkel handlebar bag was the 1st Arkel bag I bought. I now own 4 panniers and the handlebar bag from them. I just couldn't get past the mount for the Ortlieb bag plastic no sorry. Sorry to hear about your problems with the Ortlieb bag.
I know they make great products as everyone swears by them. I would return the bag to the distrubutor and take a look at the Arkel bag. Arkel has a pretty good website. You can also buy the mount separatly for use on different bikes.