need help with key fob (non SKS) programming

I am new and this is the first time I am posting here. However, when I have some issue with my car, I always find posts from this forum that are very useful to help me solve my problem. I usually found answers from some posts from this forum without needing to post. We recently got a 2008 Prius, the UK version, which came with only one key (non-SKS, black logo on the back). I wanted to have an extra key just in case so I did a lot of reading on this forum to learn how to do the "chicken dance" to program the key.
After that, I bought a used fob key (black logo on the back-which the eBay seller said was ready to reprogram, and for some reason, if I wasn't able to, he promised to take the key back). Is was able to program the first part, start the car, on the first try but failed (many times) in the second part, lock/unlock. Then I spent a few more hours reading some posts and found a post, pls see the attached, that helped me to program the new(used) key lock/unlock successfully.
The only difference in this procedure was pressing the power button 3 times (twice). However, I got into trouble!!

- As soon as the new (used) key was working both start and lock/unlock
- the original key stopped working lock/unlock (but still able to start the car)

I was so freaked out and worried that I would mess up both keys so I didn't try anything yet. I tried to find it to see if some people might have similar problems but I couldn't find it. So I was hoping some of you from this forum might be able to help me!!
Thank you so much!!

 

Hi JC91006, thank you for the response. I am quite sure which one is the original one as I marked the new one to make sure I won't confuse.
That is why I got confused when that happened. I didn't see any other member from this forum mention it before.
I was assuming that the eBay seller has erased or reset the key before selling it. What is more interesting is I was able to open the door that the key comes with the new (used), which is already cut. I can also use the key from my original one to open the door, but just its lock/unlock button is no longer working. Not sure how.

 

Yes! I know. It didn't make sense to me too.
I was a bit upset that I got a used keyfob (the seller claimed that it was new), and the manual key was already cut when I received it. I tried to lock/unlock the door with a manual key from both the original one and the one that I bought from eBay and they both worked!

 

This is not funny! I am not making up the story but just telling the truth about what happened. It is ok if you don't believe it. I myself can't believe what happened either. But please stop mocking. I am not trying to seek any attention by making this up. I am only asking in this forum to see if anyone can help. Thanks!

 

Sorry! My apologies! I wasn't aware that a house key or any key could manually unlock a car key if the car lock cylinder is broken. I thought you were asking me to do an impossible task

Thank you for the suggestion. I tried with some keys but none of them unlocked the car door. It might be because I was able to insert them only about halfway into the key slot. I will try to see if I can find a key that can insert all the way and let's see what happens.

 

That is what I thought too. I was expecting that the worst scenario would be I couldn't program the new(used) fob. Not the other way around.
Yes! The red LED is still on it.
I was thinking about that too to re(add) the original fob but didn't want to take a chance just in case. I don't want to go to a Toyota dealer and spend a fortune