Messed up my contract

she called me to offer me to go on a 199 per month package with current conditions of my 20GB per month. then in the same call I asked to have another contract for a Samsung tablet 4, now it turns out she cancelled my 20GB contract and instated the 500MB contract, for what I don't know. I called in and was given a reference number. and left message for smangele. she called me to say she upgraded my line for what I don't know. please resolve this by re-instating my previous 20 GB arrangement. my business is being affected by this issue. please do this asap.