Some ideas:
1. Have a lawyer send them a letter. A legal firm's letterhead will get taken more seriously than an email or Contact Us, and may force them to respond in some way.
2. Spin up a corporation and have it "acquire" your product.
Use a law firm or other provider as the registered address. If that's not possible in Sweden, incorporate in a jurisdiction outside your country. (This may have an impact on how you get paid, taxes, etc. but that might not matter if you're planning to unpublish).
3. Quantify your damages (eg. cost of above, security firm to do a home assessment, mitigations like installing security cameras, etc.) and litigate.
Unfortunately it can be hard to quantify damage to privacy (check for any precedents in the applicable jurisdiction's case law), and you may have already agreed to terms that prejudice this. Be sure to keep track of any disgruntled user feedback that makes you feel even mildly threatened in any way, any increase in unsolicited mailings, etc.
4. Get a short term rental somewhere, change the address to that, never update. Or use a friend who's about to move or doesn't care (eg. change the address on one of your credit cards to theirs for a billing cycle).
This isn't nice to whoever winds up at that address next.
5. Move, and don't update them with your new address.
6. Instead of selling your old home at the poisoned address, contact your local fire department and offer it as a controlled burn site for training. Scorch the earth and never look back.
Or, somewhat less satisfyingly, donate the land to your municipality as a park. Subject to a clause it be named something like "Alphabet's Reach" in perpetuity, and commission some kind of permenant concrete art installation to forever memorialize their betrayal.