MTS Broadband Service — data not carry forward although they guaranteed

Address:

Gujarat

i have mts mobile broadband usb prepaid connection. after buying this dongle lots of probelm
arise. like lack of speed,no response from customer care, site not publishing online complain
number,poor customer service,irresponsible reply, balance not shown on stick etc.
but not feasible to purchase new dongle every time to change operator.so i think service will
become good soon. but on the month of feb (23rd) my package recharge date. i have got mts sms and
site also tell that previous balance carry forward + 4 gb data with recharge of 490 rs.
so i have check balance it showed me 11 gb plus some mb.when i actually recharged the prev. balance in
my account gone only 4gb showed.then i have emailed to customer care and applete authority.
but they said that no balance in ur account before recharge and refuse to carry forward 11 gb data in my
account.
if i have no balance how i use prepaid internet on last day or why recharge of 490 give me full 4 gb
data no cutting of prev.data usage.
if no data balance in account.just answer my this que mts.
lots of email done but they refuse to pay balance data of 11gb in account. so do something.