Hmm, this is the first problem I've heard of with the upgraded faucet with the pullout. I'm very glad to have mine since I don't like the cheap handles of the shower/bathroom sink faucet.
Where is it leaking?
I do also think your best bet is to just get a new one, but hang on to the old one if you can to see where it failed. I'm curious...
2007 T-286SR Cherry/Granola, #6236, original owner, current mileage: 9467.8 (as of 5/26/19)
1997 T-2653 Blue Denim, #5471
1979 12 1/2' MC, Beige & Avocado, #4639
Past Sunlines: '97 T-2653 #5089, '94 T-2251, '86 T-1550, '94 T-2363, '98 T-270SR