internet service provider not efficient

Few days back i bought a mobily sim. As the sales person said it has unlimited acess for a month with a speed of 2mbps. For the first week it worked well but now the connect has become horrible. I cannot even open my facebook.Its really disgusting. Please make your service provider efficient for customer needs. Commitment should be fulfilled as per your saying.....instead making customer fool by saying or marketing the services which u r unable to provide.