So I have sent btc about a week ago. Because of major delays it got returned eventually. I sent the btc to my market account, this time with a higher fee and it went thru

HOWEVER I log in today to see that the returned btc from the first transaction was sent AGAIN
AND this time to the same adress, but my market account has a changing btc adress and now I have btc heading to god knows whos wallet

I never authorized the sending of the transaction the second time

What is going on?
P.S I use blockchain wallet
Im so mad it would send my btc without MY authorization or even me knowing

hello dont worry, you will get your bitcoins to your market account without any issues, your market account will give you different address which are belonging to same same, so whatever new address generated by your market account all are belonging to same seed.