Oxigen Services India Pvt. Ltd — Oxigen POS machine buy back scheme

Sir, I was running services from Oxygen Services India Pvt. Ltd company from 2017 but as there was no income from these services so I stopped using their services.
On July 9, 2019, I got call from company that if you are using POS machine then there is scheme called "oxygen POS machine buy back" is currently going on. In this scheme you have to submit your POS machine to us and we will return you certain amount against it. So I immediately couriered this machine on the same day through DTDC courier. I have attached a receipt here. From that day i continuously taking their followup but each and every time they said that the process is going on, you have to wait for few more time. Today it is 10th October 2020, I have given my machine on 9th July 2019. Still I am not getting any kind of response from them.
I am giving their contact number here, which are switched off every time
SBI Kiosk Banking – [protected]
Micro ATM/Gift Cards – [protected]
Recharge/Bill Payment – [protected]
Travel – [protected]
OMTS – [protected]
IOCL – [protected]
I am requesting you to please look in this matter and help me.
Thanks and Regards