******** i jave been ****** my. Money

Hello why should i pay R877? What happened to R698 that we agreed on when i took the contract the are othe extra charges please fix this i have been bagging you for months now last month paid R1300 this month R1100 so next month should pay R877 whereas the contract that i signed up for said i should pay R698 so how come am i paying so much?????