Is my birth certificate worth money

Sell ​​documents from WWII

Hello,

I'm not that good at negotiating or saying "no". That was always a problem for me in the past, after a while I can no longer say to people who want to sell me something "I don't want that, thank you for advising me for half an hour in vain". For this reason, I almost always appear online with the wrong (made-up) name and phone number when I plan to buy something but still want to find out more. Because if necessary, I can always say for myself: The person doesn't exist, you don't have to sign anything, just break off contact, nobody will bother you anymore.

I don't really cheat or hurt anyone. So I don't buy something under a false name and then don't pay the bill or something. I would not do that.

Now I've been looking for a car for the last few days at an online dealer that is also a little further away. And wanted to inform myself first "non-binding" and negotiate approximate contractual conditions in advance (method of payment, payment in installments, etc. pp.) In the end, however, I changed my mind. I haven't signed a contract yet and said from the start that I would think about it and then let me know whether I would take the car or not. After I didn't take it, the dealer suddenly wrote me on my real email address (I have no idea where he got it, I haven't given it anywhere) and told me that he knew that from the start and that he had anything else to say before he would take legal action.

Now I wonder what kind of legal action? I "only" used a wrong name, didn't sign a contract or said "I'll definitely buy this". I've already googled, it's not fraud for me and allegedly I only have to give my real name to the authorities, I haven't forged documents either.

What could I expect now?