I think you're being vague w/ your terms. I assume NYSEG DELIVERS your electricity. AFAIK, each region only has 1 company services them in this regard so you're stuck w/ them for that.
Likely, this 2nd company is offering to SUPPLY you w/ electricity. There are MANY companies that supply it & you can select whomever you choose.
Looks like you live in Saratoga. You'd still get only 1 bill (from NYSEG). They would charge you for delivery as well as supply (which would then be provided by your supplier of choice & the payment forwarded to them).
If you do opt for a different supplier, read the fine print on the contract. Some can capriciously change the price & it takes months to change suppliers so in the mean time, you may be paying a ridiculously high rate. That said, you can usually find a (much) cheaper rate using a different supplier, thereby saving 10% or more on your overall bill.