Spectra net not working since past 5 days - South Delhi

i have been spectra user since jan of this year. i had planned to initially disconnect after their 6 month period expired as they throttle torrents. however, i went the seedbox way and so its live able.

now for the past 5 days, weird things have been afoot with this notorious ISP:

1) every night at 12.15, the net goes down. then magically, it comes back on at 12.30! this is happening daily and neither i or spectra has any explanation for this. they are denying doing anything at their end & this is what was conveyed from their 'engineer'. despite daily complaints, no one has called me from the L2 team and the complaints are quickly resolved as net works after 15 mins.

2) on a couple of nights, the net did not go down at 12.15 & i was relieved... but oh, i was quick to rejoice. at 12.30 it went down & guess what, down for the whole night! in the morn, i checked & it was back up. what is going on is anyone's guess.

3) last & definitely the worst - for the last 3 days, my net has been going up & down every 5-10 mins. sometimes the dsl link goes down and other times the internet link is flapping. ultimately, i have not been able to use it at all. i have a secondary Airtel conn which has now become the primary conn as this doesn't work at all. even as i type, it has gone down again. an 'engineer' visited my premises, changed the modem & nothing improved. they assured me the wiring was re-done - nothing changed. now the 'engineer' finally gave up and said he does not understand the problem. he has also started ignoring my calls

i guess my only option is to disconnect once the plan expires but that is still 4 months away. i am also not sure which isp to switch to as they all have some or the other problem. i do not want to go for any ISP which throttles torrents & applies draconian FUP. i am looking for a true unlimited plan as my usage is high.

i really don't know what to do about this so posting here for suggestions and also sharing my experience so other people know.
Airtel Xstream Fiber
Airtel Fiber (FTTH) if its available.

Been using airtel vfiber for the last year and airtel ftth for a week, never had a problem.
Even at 24mbps(Vfiber) it worked like a dream , would stream primevideo and youtube at 4k as well(with a few seconds to create healthy buffer).

Use to have airtel a decade back , switched Isp when they introduced low fup.
After using mtnl , couple of little known isp provided by lcos , excitel , finally came back to airtel.

Its the most reliable internet service I have ever used. Period.

Edit: 3.3TB is the most you will get with most isp now , maybe lco provided isp might have more data maybe even unlimited ?