Eurekaforbes — Aquaguard RO | Installation charges seems to be fraud.

Aqua Guard Glory water purifier installed at my place on Feb 27 2023.
Since I am staying in high rise building installation engineer said I have to buy pressure guage to control the pressure and external filter/candle. And he asked me to pay 2805 Rs for the external filter & pressure controller.
When i asked for invoice, he said I have to pay first and then I'll get the invoice from company on my mail but that's not done.
I started chasing them, after multiple call and mail finally after six months they sent an invoice. But that invoice mentioned so many things which is not at all installed at my place. and now when i chasing them they are not responding.
And as per another engineer from same company, installation engineer has taken around Rs 500-600 extra from me. Amount should not be more then 2000 for this.