Signed for 2GB data only get 1GB data

I signed with Nashua Mobile for 2 GB data on 01/10/2014, Nashua Mobile's customer were all taken over by Vodacom, after Vodacom's take over I only receive 1GB data. I have send all documents proving that what I signed with Nashua Mobile to Vodacom and thus far no reply from them except that their system states that I am on a 1GB contract. I also made 4 phone calls without any success.