Associate Stole My Coffee Brand

So long story short I sold 80% of my unregistered coffee business in France/Spain to a guy I met on Reddit. We did a contract where he would handle the roasting and I all the day to day marketing, operation, etc and he would pay me 300 euros per month. After 1 month he stopped replying to my texts and emails and said I didn't have any authorization to continue with the brand or to refund any orders (I refunded an order after him not answering me for weeks because I didn't know if he was actually roasting the coffee) he threatened to take legal actions and blabla bla. I was astonished but then he blocked all my accesses to our webpages and instagram. This guy has a name in the coffee industry in France and has a coffee shop in a small town. I told him he can keep the brand but just pay me what he owns me (300 Eur of salary plus my 20% of the brand) but hes just ignoring me. What should I do? Legal counsel would be worth it for 500 Eur? Maybe I can ask for more since ha has a business? I have a signed contract that he broke but not sure what to do now. I told him I was going to denounce him to our clients and to the coffee industry and this is what I'm doing more or less.