I would use the razor if you can. I need to do the same for my Steiner. I have used scissors and once actually snipped the skin. If you can cut part of the mat (farther away from the skin), sometimes you can then pull apart the rest that is closer to the skin. Steiner is patient and usually lets me pull the smaller mats apart but there are some more complicated ones in hard to reach areas where she is less less tolerant of my fiddling.

Thanks for all the help, will get back with results

I distracted my girl Lucky, who also doesn't like to be messed with, with a brush and scratches while I used a scissors with the other hand. I wouldn't recommend this unless you have a steady hand and are able to get under the mat, as it's easy to cut their skin that way. There are de-matting tools sold online and probably in most pet stores that cut the hair without risk to the skin.

Two other options are to buy an electric razor yourself and do a few at a time. It helps to have one person to hold (using a towel wrap) and one to do the grooming. Only shave out the matted hair itself. Not the entire cat which can interfere with heat regulation of the kitty.

Or buy a small grooming razor such as this.[amazon.com]
It makes less sound and will get close to the skin and not cut.

I have become very deft with fingers and human hair cutting scissors - but I have years of practice on my side. I'd never have attempted that my first time. lol

do a few at a time. If you have a sharp small scissors it will work best. Just cut the mats out, being very careful not to cut skin. Do one at a time, let her get accustomed to having it done. You will need to start brushing her daily to avoid the mats, if she will let you. I've never had a cat I couldn't handle or manhandle. So she might not let you. You may have to go with the vet. The mats are painful, they get so tight they pull the skin.