i don't have a matrix but I read the datasheet and to my surprise the connections are not in numeric order. So it is not 0-7 from the first to last leg. Check the links in previous messags in this thread. Direct link to a datasheet: 2.3 Inch (58mm) 8x8 White LED Dot Matrix Spec, Data Sheet LC2088TW1C from lc-led.com
If possible try to use more than one colour for the wires. It is so easy to make a mistake and you won't notice it. You can also try to switch on 1 row, use Massimo's code with something like this:
max7219_put(0x01, 0xff) Here 0x01 is row1. So, try row1 to row8 and see what led's switch on. Rewire row for row until it works.
I made a circular matrix with the driver, wiring the whole thing was a challenge but using different coloured wires certainly helped. Figuring out to which rows the wires were connected to was time consuming but worth the effort. I haven't put it in the playground yet because making a circular matrix is apparently easier than writing in the playground. :o