Tvs Credit - Phone locked unable to use

I taken consumer loan in tvs credit every month *rd is my emi date amount is in my account but they not deducted I went directly vivo showroom and I check with tvs credit employee he said signature issues for that unable to deduct money in ur account that month emi amount I given phone was un locked but my problem not solve next month also same problem if I ask call that person he not picking the call and he received the call also roude behavior now phone also locked unable to use he asking extra amount den only phone will unlock other wise phone will lock he blackmail me he not resolved my phone he asking penalty amount