@Shubham They do support 3rd party ONTs but my case handler told me that they wont provide any troubleshooting if anything goes wrong with my connection.
So in a way, if your internet doesn't work fine and you are using 3rd party ONT they wont take your complaint unless you get BSNL provided ONT.
Atleast that's what he told me, but then again, he could have told me this because I am already having this issue for over 6 months now and introducing a 3rd party ONT might increase problems for him, because he might not have any experience on other ONTs.
So in a way, if your internet doesn't work fine and you are using 3rd party ONT they wont take your complaint unless you get BSNL provided ONT.
Atleast that's what he told me, but then again, he could have told me this because I am already having this issue for over 6 months now and introducing a 3rd party ONT might increase problems for him, because he might not have any experience on other ONTs.