Do I get my money back?

My former "best friend" and I have agreed to share a Netflix account. It was originally agreed that I would pay for one month and then her for the next. After 4 months when I paid the account, she always had an excuse not to pay (4 × 15 = 60 euro). Now, after an argument, I don't want to have anything to do with her anymore and want my money back, but she doesn't want to give me back the money (I've asked her about the money before). Her cousin also interfered (she is 18 the cousin) and also threatened me that she would beat me up if I asked my "friend" again about the money. The problem is my "girlfriend" has moved to Cologne and I still live in Bavaria, which means you can't meet. I wanted to ask if there was a legal way to get my money back and to file a complaint with the cousin who threatened me (I only know the cousin's first name).

Whose name does the contract come from?

Netflix sees exactly THIS from which is allowed to pay. You have verbally agreed something, THAT is the problem; not provable.

the one who signed the contract pays. He has no claims against his girlfriend

It's not even allowed to share Netflix accounts this way. In addition, your agreement wasn't even with a contract or something like that. Held on, so it is simply not possible to get the money "back".

The contract was in my name and my "girlfriend" and I agreed not only verbally but also in writing via WhatsApp (I still have the chat).

We agreed on WhatsApp.

Apprenticeship. Either you agree directly that half of the monthly payment is made or you change the access data after the first excuse.

Afterwards, I wouldn't open a barrel with the sum. On the one hand because this sharing is not necessarily allowed, on the other hand because you have no way of getting it back without throwing good money afterwards.

As far as I know, that wouldn't count as evidence in court.

Why not change the password etc? She won't come in anymore

I trusted her and assumed she would settle it

Change the credentials before she does that. Anything else, no matter.