I'd adopt comm failure procedure as well as trying to call via iphone or try to catch some wifi network.
Interesting point... I haven't researched too many places so I don't know how many places this applies, but for my home base (in France), the French AIP charts include the control tower telephone number and highly recommend it should be used via mobile phone in the event of lost comms. Strangely, the Jepp charts we use don't have it, which is not particularly helpful if that's all you have on board the aircraft and you need it...!
This would also suggest they'd prefer you to sod off to the hold even if you are in VMC allowing them time to sort themselves out, rather than you frantically trying to call while you're downwind at 1500ft for another approach.