You are playing "best hand" daylong GIB event and reached to 4♠ in North. (you are south but human declares)
You receive ♦4 lead and after 3♥ bid you do not need to be physic to guess this is a singleton.
So you won in dummy(south) with ♦K and and play ♠T, A, 5, 3
West now plays ♦J, 6, and East discards ♥3 and you win with Q in dummy.
Now you try another ♠, 9 ,4,6 and East wins with the ♠J.
East plays ♣9 which you win in hand with the K and play 3rd ♠ which is won by K in East while West discards ♣8.
East now plays club 7 which you win in dummy(south) with the A.
Did you count the hand of East and/or West?
If so the hand is an open book at this moment and you have a lock for 10 tricks despite having already lost 3 tricks and still holding a ♦ loser.
I will leave it to you to work out the rest of the hand. As a novice or beginner or an intermediate perhaps, to be able to count the opponents hands is what you need for now and whether you find a solution or not after finding out their shape is more like intermediate material. If you could not find how to play the rest of the hand after counting their hand, it is OK. I or other members will get back to this and tell you how to handle the 4th ♦ loser.