if Telecom sales agent said that they will take care of it, then it's their responsibility. I suggest you bring it up with them, let them know that this is the ONLY reason you transferred service to Telceom.
if the peson you talk on the phone can not resolve this, ask to speak with a manager or a team leader, they will be able to sort this out.
if manager or teamleader can not get this credited back, ask to log a formal complaint and give them 10 days to resolve this, let them know that if not, you will be contacting TDRS.