Your interpretation of the EU law is correct, Art. 27 says
The consumer shall be exempted from the obligation to provide any
consideration in cases of unsolicited supply of goods, water, gas,
electricity, district heating or digital content or unsolicited
provision of services, prohibited by Article 5(5) and point 29 of
Annex I to Directive 2005/...
If PayPal are in breach of their contract you can sue for damages
Economic loss is calculable and there are various methodologies for doing so. Your lawyer will probably have you engage an expert witness to do so. No doubt PayPal will have their own expert to explain to the court why your expert is FoS (and vice-versa).
However, it’s extremely unlikely ...