Thank you Jerry,
let me explain my situation. I really wanted this mount but it was not in stock and it will not be in stock till May-June(checked with ES Aria Boroojeni - Customer Service).
But suddenly there was one available at FLO UK as a return from the customer. So I contacted FLO they tested it and it was working so I took the risk and bought it. I'm in EU Slovakia.
FLO - 700EUR
CUSTOMS - 200EUR(non refundable)
I have contacted FLO about this and they said that the reason for the return was the same problem I have now. But because it was working in FLO they thought it is OK.
Now I want to fix the problem here if I can because I don't want to deal with the customs again. I would have to pay the fees anyway even if it's an RMA claim. (less but still)
So I can't return the mount because of the nonrefundable 200EUR customs tax+fee.
I don't want to go straight to RMA because of additional costs. I would do so only if you say that there is nothing I can do here.
Another option is to send it to Bresser in Germany but who would cover the cost? I'm also waiting for the answer from FLO because they have contacted Bresser already.