I must be a technician

Called Vodacom 28 May to advise that 1GB data I bought I cannot use because of reception. Was told to try another device. I travelled and it worked. Got back and again the same story. Now the data has expired and they (Kwanele Mhlongo) that it was my responsibility to let them know there is a problem. Am I their field technician? We agreed that I would have use of 1GB of data for 30 days. If I called on day 29 it should not matter. Also, the call centre does not have even a manager or supervisor at night. They operate on their own. Was given the name of a manager (Nolutwe Mabadlela) but warned that I would not be able to get hold of this person. I want my data or my money back.