they are misbehaving , abusing and talking in a very bad manner , and not even listings my pproblem

I have tried many times to convert my no.8149917561 from post paid to prepaid .
I have completed all the formalities for that , even I have paid 15 days advance payment as par they said , on date 27/06/2018 ,Bill receipt no. 291085501

but now they are not agree to convet my service from post paid to prepaid , they are misbehaving , and talking in a very bad manner !

pls help me !