I am sorry to hear about your experience bro.
In that case, the technician has only sent OTPs for device activation but not the final for SR / workorder closure. This is why you might be facing this issue. It is a fault on their end.
I would advise you to write a mail to Airtel's Appellate Authority of your region on the mentioned mail -
Airtel Broadband Appellate, Airtel Fixed Line Appellate, Airtel Broadband Fixed Line Appellate
On your email, you can mention your issue and also explicitly mention that you are differently abled person and can not visit Airtel store. That way the Appellate Authority may coordinate with local Airtel office and help closing the SR so you can finally access your account details.