I experienced almost the same problem when I sent ETH to ETH address on yobit.net
And I noticed that the wallet on yobit doesn't show any indications that there's an upcoming ETH that came from my outside wallet address but later on it was done successfully.
6 days of wait is very long and it's an unusual delay, have you ever try contacting yobit support? (Oh well their support sucks).
The problem is that you didn't provide any txid for us to see if you did successfully sent it to their ETC wallet address.
Blockchain explorers didnt show txid to yobit and i have no idea why. It looks like ETC still on wallet.
I wrote in yobit support yesterday and still did not receive a response.
Show us your TXID here so that we can tell if it was successfully sent to the other ETC wallet that you intentionally sent it.
Just like what I said with the yobit support, they do really sucks. You'll be one of the luckiest person on Earth if your query will be noticed by any of their support.
Try to tweet or message them in their twitter account too, they seem to be active there too.