HTC One failure

Less than 3 months after purchase:
. the jack already longer works (and therefore farewell handsfree to phone, or listening to music).
. The sound in speaker is not terrible
and so I am obliged to stick the device to the ear, which is not practical because this phone is one of my working tools. Often at the same time I have a caller on the phone, I need to have my hands free to use my computer.
I am furious at this failure of the jack.
While my phone is being repaired, how can I do to reach my clients, or receive their calls ??
Frankly, it is lamentable that a device that costs more than 500 euros is already down less than 3 months after purchasing !!
And besides, after sales of HTC service is not indicated on the Amazon site.