Made in Maccas wrote: ... how long will it take to ... get my phone back?...
Ask the store where you have the appointment. They may have different service standards than Apple's one week in Australia or 3-5 business days in the US.
Made in Maccas wrote: ... Will Apple provide me with an alternative one to use before I get my phone back?
Ask your store.
Apple offers that service option (Express Replacement Service) for your decision, but your local store may have different terms.
For example, Express Replacement Service cost depends on your country location and your Apple Protection Plan. You don't give a location, but if you are really in a Maccas and not covered by AppleCare, there may be a 39 AUD charge for the service. If you are in the US and not covered by AppleCare+ or AppleCare Protection Plan, a $29 fee may apply. Your local store can quote you the actual amount depending on your specifics.
Message was edited by: EZ Jim
Mac OSX 10.10.5