This is not explicitly covered under EU261, as the airline's obligation is to ensure that you arrive at your destination airport. Exception to this could be if the ground transportation services were either provided directly by the airlines at no additional charge, or if they were offered by the airlines as a bundled purchase, but executed by a 3rd party.
Each individual airlines may have policies that extend beyond minimal requirements of EU261 and you should appeal directly.
It all comes down to their individual interpretation of Article 9
Right to care
1. Where reference is made to this Article, passengers shall be offered free of charge:
a. meals and refreshments in a reasonable relation to the waiting time;
b. hotel accommodation in cases
- where a stay of one or more nights becomes necessary, or
- where a stay additional to that intended by the passenger becomes necessary;
c. transport between the airport and place of accommodation (hotel or other).
2. In addition, passengers shall be offered free of charge two telephone calls, telex or fax messages, or e-mails.
3. In applying this Article, the operating air carrier shall pay particular attention to the needs of persons with reduced mobility and any persons accompanying them, as well as to the needs of unaccompanied children.
For reference, here is case precedent with a woman suing Ryanair related to EU261 claims - http://curia.europa.eu/juris/document/document.jsf?docid=133245&doclang=EN