Scam chatline invoice

FLUFFY

Out of the blue I received an invoice from a Czech company called HOECK (though the postmark is in Germany) for £75 for a "telephone sex service". It had my full home telephone number which is unlisted plus the date and time of the supposed call. If not paid within 8 days collection charges would be charged.
Although I knew I'd not used the service it unnerved me but checking the calendar I saw that I wasn't even in at that time. My husband also denied all knowledge!! As the telephone and internet is in his name I thought it was probably a scam.
It gives a PO box number in the Czech Republic, asks for the payment via Paypal or transfer with details. You can contact them by email but I didn't want to give them my email address as another way of contacting me.
I've reported it to Action Fraud but other than an acknowledgement I heard nothing more.
Yesterday I had another invoice for £120 as £45 default costs had been added. If I don't pay within 8 days "we will be forced to take further steps against you. Any further costs of this procedure shall be charged to you."
I contacted Action Fraud via online chat and they advised me just to start a new report and continue to ignore the letters. I will do but it is unnerving.
Can I report them to Paypal for attempted fraud? I've not found any other reports online relating to HOECK but there was a similar thread last year about Czech company with German postmark but no follow up as to what happened.

JJ_Egan

Via google
https://forums.moneysavingexpert.com/discussion/5712960/new-use-of-telecom-billing-scam

FLUFFY

Yes this is the one I referred to but there's no follow up as to what happened next.