[tommyallen]

Have your calls forwarded to a service you can answer from your computer. Securely strap your phone to the back of an outdoor cat. Be sure to set a strong passcode so the cat can't use the phone. To keep the phone charged, invent a charger that can convert the kinetic energy of the cat's attempts at walking away from the phone. Use the money earned from your invention to buy more phones.

[TheSpiceIsLife]

You could harvest the energy to charge the phone from a perpetually rotating cat by strapping a piece of buttered toast to its back.

[delinka]

I believe this method is patented and isn’t due to expire for another 12 years.