How do I fix the carbon contact of my blender Girmi TR20?

I have a Girmi TR20 and I need to change the carbon contact. Where I can found it? They need to be the same type of carbon or it's ok if they are a little bit different in inch? Could I modify them with a mini tool grinder?

crwdns2934089:0crwdne2934089:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2889612:0crwdne2889612:0 0
crwdns2934285:0crwdne2934285:0