Okay, so if 2FA is impossible to be removed, here is a plan.

Step 1) Write EVERYTHING down. Take picture of everything (internet history of you accessing the site - if need be). Find any email or record of you making any transaction.

Step 2) Consult low cost legal advice in your town. Be willing to file a sworn affidavit that YOU purchased 5 BTC and have them stored in blockchain's server(s).

Step 3) FOLLOW THE LAWYER'S DIRECTIONS. Sue blockchain's LLC if need be, as it is YOUR money, and its office in the USA will be a place that can be served.

Good luck!