MTS / Sistema Shyam TeleServices [SSTL] — Network not working

Address:	600095
Website:	google

Sir I have subscribed for post paid mts india data connection on 25/10/2915 No [protected].I am in the monthly plan of Rs 599/Rs 687 with tax.I have paid Rs 1300 for data card.From the begining the net work was not working properly.I have madeseveral complaints.all gone in waste of time, Finally I requsted to change my plan to prepaid.The CC asked me to clear the outstanding bills to local outlet Maduravoyal, Chennai.I have made payment of Rs 686 on 12/01/16 and given all my documents to change pre paid . I have paid Rs 200 for conversion bill no 6960 dt 12/01/16.now the problem is, the retail outlet at Maduravoyal says that we can only change the plan only after 4 months i.e 25/02/16.on contacting the cust.care, they directed me to contact retail outlet.In this connection I have fedup and being a senior citizen, I am helpless.I could not understand why I must pay for my irregular service providers?Is there any possiblities to take legal action?