this is my first time but I think I love this app

<p>Hi there I have a big problem.can anyone tell me what to do,I have a Mrp mobile contract and for months I didn't use that sim card.For the first time in August I use that sim card.my payment per month is R129,00 last month I pay R500,00 and this month I received a message that I must pay R2898,68 There's no way that I pay that money think I changed my account details.I send a email but there is no response so can anyone tell me what to do .thanks</p>