Same model, different hardware, how to find parts?

My 4TB WD My Passport, stopped working and an expert viewed it and told me that the head needed replacement, and i should buy another one, same model. I did it, and then we saw that the old one had 5 sets of needles because it had 5 disks and the new one has only 4 and it doesn’t fit. I really need the data that i had on it and i have already spent too much money on it.
What should i do? Where can i find this part?!
Thank you.

Try to find on Ebay for that same part number and with the year that it made of another old hard drive?

can’t find it… and the drive alone is too expensive, i already bought a new one and it was different i don’t want to risk more money… i just want that one part

Maybe you can find the part number or search Google/Bing for it? It is very rare people would by something like this to fix the hard drive. Those that fix the hard drive would know where to get the parts. Good Luck