APN - No data throughput - No Resolve

I have a national APN with vodacom for 3 years. This APN is used for monitoring multiple stores nationally. Last year April, i noticed a declined in data throughput and the network becoming unstable. Although the signal displays a good 3G strength, there is no data throughput. In june 2014 vodacom installed a signal booster in Kenilworth, however the declining state of affirs has rendered this attempt null.. In October 2014, they once again tested and closed the fault report within 2 days. No one has reported back to me. the service continues to deteriorate and vodacom refuses to fix the issue. The worst matter of all is that their technician asked me how to test the APN !!! If a national ICT service provider lacks the skill to handle network issues, how are we expected to maintain our livelihoods? The integrity of the service offering is lacking.