Planning to Install wireless broadband at home from a local ISP

Which things to consider while taking a wireless broadband connection from local isp as i live in a small town ..

Last time i took the wireless broadband connection in 2018 and guy took 5000 rs for one month plan and devices , it worked fine 2 -3 months and after that it started giving issues like speed and ping drops , so he visited 2-3 times but again same issues ,then he changed my radio antenna but again same issues so i surrendered it , and he gave back 1000rs to me . 😒

Now i want to install fresh connection again .
The ISP guy is asking for 5000 rs ( for antenna and router )
Shall i buy a antenna and router from my own ? will it be cheap rather than paying to him .
What other things shall i consider like values and settings for proper stable speed and pings. Those installation guys are really illiterate and just know how to install it and check speedtest (ok speed is coming ...) then get away .

If you planning to take FTTH connection . ask your ISP "can i buy broadband modem from outside". if they are not willing . buy cheapest broadband from ISP and buy a router from online with dual band support it will help in speed variation and high performance. if they agree to buy modem from outside ask them what about their required specification + dual band support (means support 2.4ghz+5 ghz).

Is your area unserviceable with a Fiber ?

More information please.

To not to burn your hand again, just in hopes that things might turn out well this time due to one reason or another, I would advise you first ask them about what wireless core tech are they using to provide you internet like EVDO, private LTE, etc...
Then ask them about what tech WISP provider is going to use for you, Ubiquiti(What BSNL AirFibre is going to use as per info posted here), specific antenna devices/types,etc..
This will help you factor out if your geographic conditions are compatible with their wireless tech or not.

Consult them about their upstream provider and what tech is upstream provider recommended/given them , the guys might be dumb so if you ask nicely you might get answers .( has upstream provider for e.g like BSNL has strected a 1-10 Gbps cable from main office to your WISP reseller)

Also scour for more info like other customer reviews,etc.

Then only go about finalizing the descision.
(Don't forget to bargain as much as possible. Just be nice about it)

You guys did not answered shall i buy radio antenna from my own ???

Well if you already decided to seal the deal.

Nope, unless you know the exact antenna and signal converter model.
You might be tempted to buy a cheaper or more value for money antenna of different model or worse different vendor and then it won't guarantee if it will be compatible with your Wireless ISP(WISP) own antenna ,etc..

ALso without knowledge of upstream provider and their wireless stack and your geographical topography we can't say anything about your speed/ping stability.