hutch cannot be trusted.

I had taken two postpaid nos and intercalling between these two nos was as said was free. when my cards were activated i started calling to the other no(Hoping for free calling) . But after four days i realised that i am being charged for these cals. So i went to hutch gallery, Aundh and i told them my query.
The lady at Hutch(employee) assured me that the amount whatever is mistakely charged will be deducted when the bill is generated for next month. I asked in writting, but because of faith or trust i kept on that lady i didn’t took in writting.
Now the lady has left the Job and hutch (Aundh gallery) is giving reason that lady has commited something wrong , she has left the job and so hutch cannot deduct my bills.
I ask hutch whether Hutch commitments is restricted to person and whether the employee doesn’t represent HUtCH.
I am being fooled and sorry to say hutch cannot be trusted.