Hathway — received bill even before internet service started

Address:

mumbai

I was contacted everyday by sms regarding hathway connection for rs 599
I paid 599 rs and they came the next day and flitted the wire
Saying they will come with the modem the next day
3 days have passed no modem no connection no internet
But i receive a sms that i have to pay a bill of 198.1
Bill for 10 june 2020
Due date is 22june 2020
I contacted the person who had first contacted me mr mohan mobile no [protected]
He told me to call a land line no [protected]
I was directed to speak to installation department spoke ms preeti
Very rude in speaking
Who told me to contact billing department
Who then say i have been charged for overdue
I asked them to discontinue the installation and refund me the 599rs which i had paid
But they said i have to make a complaint etc
Can some one advice me as what i should do
Thank you
Stanley