Question about blocking

I happily parted ways with my ex with bpd and blocked him everywhere I could. The peace I've felt since has been unmatched.

However one thing is bugging me, I can't figure out how to block him on instagram as he blocked me there first. Ideally shouldn't bother me but it does, I don't want him to be able to contact me there either.

I deleted our instagram DM thread a while back don't remember why, so I can't block him using that. Can't find him by his username, comments or likes from my posts. Anyone know a hack?

Thanks x