I’m honestly a bit puzzled why so many people seem to think that getting a replacement power supply for QC is such a challenge; yes, the wire on the OEM one does not seem very strong, but IMHO it’s fine for use at home. For something more robust, a few people have bought the QC specific replacement power supply from a company called Myvolts; I got one and to my surprise it isn’t a negative polarity one like the OEM supply, instead it is a positive one and it comes with an polarity reverser adaptor.
As soon as I discovered that the Myvolts one only works with an adaptor I realised there in fact there are LOADS of different options, if you are ok with using a similar adaptor. Amazon have many different, positive polarity, options, and personally I prefer to use an adaptor ‘tip’’ rather than an adapter cable (I don’t really want any more random bits of cable attached to the unit. The adapter tip looks like the one in the picture, I got mine from eBay in the UK.
So now you can reverse the polarity, all you need is a 12v supply, that is ideally 3 amps. BUT you can use 2amps, and I know a number of people have had success with a 2 amp supply. And you are correct, support say it is ok to use 2 amp.
Here is a couple of examples of power supplies that will work, WITH an adapter. These are from Amazon UK, but hopefully will be easy enough to find something similar where you are;
