Extreamly dissatisfied

Im so disappointed in Telkom, I have a 60GB day and another 60GB night data monthly contract. The first few months were fantastic , i could not even use all the data but the last 2 months i experienced so many problems, i only recieve around 15GB of 60GB ... ? Im phoning but is holding every time over 30min with no answer, when I go in store the system is offline!!!! Im so so disappointed and negative and dont know what to do anymore