Mobile Virtual Network Operator (MVNO) is an important part of the telecom domain. It fulfills the requirements of specific groups of customers who do not use the services from major operators in the area. For an MVNO, it takes a long time to establish trust amongst customers. Then comes the stage when it starts earning money. But due to inaccurate and inefficient billing and charging, the monetary success can be hampered. So, it is important for MVNOs to not use mediocre and rudimentary billing mechanisms. Instead, they need to utilize a convergent charging system for greater billing accuracy and revenue assurance.