What is the maximum time you waited for a CLAM withdrawal from Poloniex, from issuing to completion?
I lately got a withdrawal showing "COMPLETE", with even a txid, but coins didn't arrive yet and the txid is not to be found on the explorer.
It is already a couple of weeks this happened and Polo team said they will look into the issue, but nothing changed since then.
Similar experience here. Just a couple of form replies and then it was fixed, without any explanation, or addressing my specific "this keeps happening" concerns.