Hey Swapd community,
Well for starters the solution was found by @euroemarketing 
I thought i’d do the topic as i was the seller in this transaction.
What happened is that i used to own an Instagram account with my friend who lives in Italy and owns an android device. My friend didn’t have the time to post regularly so he gave me the account as well as the oge gmail that he created on his device. He added a recovery phone number from a temporary app where you can receive the code on this number so he won’t use his phone number and then he lost access to this temporary phone. As we were proceeding yesterday and today to transfer the account, i removed this phone number with a prompt on my device and removed all 2fa . When @euroemarketing took the account he wasn’t able to change the password as they were asking to send a verification code to this number even if it was removed from the account
Solution
@euroemarketing added his phone, removed all phone activity removing everything. He then logged out of the account and clicked reset password and his phone number appeared in the option and voila problem solved.
Hope that this topic helps future buyers/sellers as this problem took us 2 hours to fix 