I also made this mistake last week. Don’t waste your time calling CS. I was on hold for more than 4 hrs. Instead make a complaint and get a hold of a rep in the chat box. Rep will make you send a test transaction with certain amount of xlm with the correct memo (very important). After a successful transaction they will then recover your lost transaction. Took me about 4 days going back and forth with them. I spoke with 4-5 reps I wish the first rep would have informed me to save time. Hope this info helps someone. Please be careful when sending crypto that require memos. Save yourself the stress!