Smart key not working after battery removed

[Maverick Gav]

I am new to this forum and need some quick advice please. I had to call out the RAC for my XF a battery issue which turned out to be the alternator. The technician got the car started and the plan was to drive me to a garage with a battery pack attached. The car was running but then everything on the dashboard went off and then the car shut down. The smart key worked fine, opened the car and started it however, afterwards the car would not pick up the smart key. The RAC technician got the car started after approx 1hr 30 min of messing around using the sensor in the drivers footwell (diid not even know this existed, no idea with cars and four years of owning this car never had any mechanical issues)

the alternator was replaced by the garage, all good but the smart keys are still not being picked up. Jag tried to recode but couldn’t and they have said I have to replace the keys. A further £617 with recoding. I am at a loss with what has happened, I think it is something the RAC have done when disconnecting the battery and or applying the battery pack when the car was running. All I know is I have not had any issues with either of my keys and now they are not working?? 
 

I have key cover on my breakdown but they are not interested as they are saying I can’t associate it with anything and they must have been faulty.they also damaged my key... rubber seal off and plastic broken exposing electronic board... must have been dropped but nobody taking responsibility for this. 😡

What has happened here, any thoughts would be appreciated?