Hello i believe bitcoinvanitygen.com stole my funds too. As i. Used their service to generate the following
1ACiD2jDZkZzeuEHA5yKuY3RKbobRVzLQG I had
BTC4.17 BTC when i noticed the following unauthorized transaction to a completely new address followed by a small transaction to empty my 1Acid account to new different address please investigate this as when i emailed bitcoinvanitygen.Com i got the exact same email that you got there is no possible way that mycelium wallet protected with a pin code send transactions by itself. I F$###NG begged them i got the same email you got.
Unauthorized
https://blockchain.info/tx/fd253e281dd4ad3952cdb2b717dae41ee3d2f6140842e031cbd1d20978cef32c Unauthorized
https://blockchain.info/tx/8762719341ed330edf80e2694e77c0b9f30a1799ae2f4f6a8c22311ba7372bbfAddress generated from bitcoinvanitygen.com
1ACiD2jDZkZzeuEHA5yKuY3RKbobRVzLQG I had other addresses on mycelium wallet and they contained some mbtc which i did not lose only with bitcoinvanitygen.com

Please advise