Another method of blocking an account.
Terms:
1.Target account must have <10k followers, the fewer the better
2. Target should have a human profile picture (i.e. a picture of a human)
3. Instagram account with over 30k followers (can be fake, process is automated the majority of the time)
Steps:
1. Change your account name to something closesly resembling your target. So if your target is hhh, change yours to hhh_ or hhh1. Change your account picture to theirs, and if you're feeling super excited upload a couple of their pictures to your acc. also.
2. Fill out this form for impersonation: https://help.instagram.com/446663175382270
3. Wait patiently
Note: I didn't try or create this method, I just found it and it had good reviews so I decided to share it!