Yes, they use and believe in them. We can see this from shuls, the places they use to pray, as the 10 commandments are written and hung up. They also believe in the 10 Commandments since a great historical figure, Moshe was commanded to write them by Hashem, the God. Many people want to follow in Moshe's footsteps so they follow the 10 Commandments.
Hope it helped! :)