Not internet. BSNL person couldn't fix it.

DSL modems available in the market are mostly of substandard quality regardless of brands.
Because no one cares about DSL modems anymore and this is been the case for the last few years.
Regarding TP-Link products, I have owned multiple tp-link products and I am yet to see them die. But they don't provide proper firmware support like Netgear does but still tp-link products perform good and it's cheaper.

After countinuesly complaining in twitter for days today a lady from bsnl exchange called me to tell that it is some migration issue and will take 1 month to fix. She also warned me not to complaint on twitter.

@firofame why not to complain , my god now they are trying to become sarkari DONS

A similar thing had happened to me with MTNL mobile when I posted my complaint on twitter. The DE came to my house to request me not to post on twitter, he gave me his card & asked me call him directly. Even his boss called me up for the same reason. Which i did till he retired. 😁 Infact I used to contact him on whatsapp. 😄😄