[MeeRKaT]

Was the engineer in a hurry to leave ? because thats how they get paid speed = quantity not quality ( I hear that somewhere else as well )
I hate seeing a VM repair van close to where I live as in the past I have twice had my cables accidently unplugged unknown by the engr who was working on someone elses problem at the time , it is very aggrivating although it does keep the engrs in work or am I really just being cynical (once is accidental ,twice is careless or on purpose.)
Maybe thats what the engr did to your phone ?
I was wondering because of the timings on your cutouts if the problem might be due to an error on their overusage policy (not yours) and it is being done by their software ?
Anyway your next call(at least when you can make one) should see you receive a new superhub only then can you prove that it is or isn`t hardware based.
Keep us in touch with how you get on