The coin (JWL) you are trying to deposit in Yobit has not been in trades much since July. So, i guess that is the reason why its network is totally jammed as there aren't any miners for this coin for sure, and that is the reason why your transaction is not getting confirmed.
You are absolutely correct on which there aren't miners wont really push out that transaction which means this coin would really be considered as dead and for OP its better to moved on and don't mind on those coins because they are just totally sh*t coins and also Yobit isn't really a good exchange to use when making up some tradings.If they do said that wallet is on maintenance why you did still deposit?
Thaught, that yobit disables deposits, when wallet is under maintence. Maybe they disabled the wallet, as they saw the issues.
These people are right, we can't do something about your problem. No miner, possible maintenance for your jwl wallet and yobit is a well known worst exchange.
what can I do ?
Contacting them is hopeless now, they have a worst support but still try your luck. Contact them again for the nth time.