I'm being bounced back and forth

I went to Telkom store in Richards Bay on 13 April to reduce my data contract from 20G to 5G. The lady told me they do not do any changes to contracts in the store and I must call 081 180. I called the number and they told me I cannot do that over the phone I must go to the store. Can someone please tell me what's the correct procedure? If you tell me to go to the store please notify them first to help me because I do not have time to go que at the store only to be turned back again.