Sold phone without reset

[campfreddy0]

Hi

My S21 ultra went wrong, long story short samsung said its beyond theory repair capability. 

I sold it on ebay as spares not working, now the buyer is saying he's got it working but is asking for my passcode so he can reset it? 

Now I'm worried about all my info on it. What can I do I signed it out of samsung remotely which I'm guessing may be a the wrong move 

[BandOfBrothers]

I would personally stick with saying I sold it as spares only and nkt a working model to the buyer so am unable to provide any of my personal login credentials @campfreddy0 

[campfreddy0]

Yes what I mentioned and told him in the messages..
He got it cheap the phone is immaculate, to be honest if he is clever enough to get it back up and running then he should be clever enough to realise that the phone would still have my security details on it if he got it back up and reset.
I said he got it cheap enough he'll have to pay someone to crack the security.
I've seen on YouTube you can do something with voice activation as a work around.