Yizo Digital pty Ltd not paying for outsourced services

I have delivered my graphic design services to them and finished off two complete signage design jobs. One of the owners Junior Summers is now avoiding me by not paying me for the jobs i invoiced him on already that was done printed and put up as well he has before come back to me with numerous excuses to keep me hanging. If you are looking to do freelance Graphic design work please avoid working with Yizo Digital as they are *******s as I am not the only one that ran into this with them.