C-CEX finally completed HEAT wallet integration about 24 hours ago and have enabled HEAT deposits and withdrawals to their user accounts since then.
Alcurex has publicly announced they are processing HEAT withdrawals of over 1k HEAT manually currently.
Openledger is in good contact with us and although delaying HEAT integration rather long they're in that process and meanwhile fulfilling withdrawals when you can get in contact with their support.
Heat Ledger Ltd doesn't operate those exchanges so all our information is second hand only.
Heatwallet.com exchange connects directly to your native HEAT wallet, without any need for deposit / withdrawal of HEAT. You can buy and sell HEAT instantly for BTC, with auto gateway of BTC deposits to your Heat wallet. BTC withdrawals are processed consistently in about 24 hour intervals.