this is a good lesson to double and even tripple check where are you sending your coins to
lucky you you had the keys to the address
I had a similar situation a couple of years ago,lost 4.2 litecoins this way,sent them to a bitcoin address at an exchange
evidently,support could not retrieve the coins due to them having no access to the client's private keys
so I had to give up trying to escalate it,besides the sum was really low at that time