That's strange! I have used yobit for a long time and have never faced such issue. However, first check in blockchain that your transaction is confirmed or not. If it's confirmed then the issue is on yobit's part. Only their support staffs will be able to assist you.
But if the transaction bis not confirmed yet, the probably you can use some transaction acceleration service. But I don't think a trans would be pending for 3 days in a row. Check if the network relayed the transaction properly.
Sure, a transaction can remain unconfirmed for 3 days in a row... If the fee was/is low enough, a transaction can remain unconfirmed up to the point where most of the nodes just drop the unconfirmed transaction from their mempool.
@OP: if you can share the funding transaction's txid, we can have a look at it if you want to...