Kitchen faucet stopped working after using the spray. Now water is not coming from either of them. It happened to me a few months ago and after a few hours it again started working. No such luck today.
I checked the following things so far
1. Water supply is still on. Dishwasher is getting water from the same line.
2. Opened up the aerator from the faucet. Still no water.
3. Opened the spray attachment. No water still when I open the liver.

Was reading online that it may be related to diverter valve. Opened the cap on the faucet to find a nut. Went to home depot but could not find a suitable allan wrench to open the nut. I have attached the picture.

Home depot told me that do not carry diverter valves and to contact the manufacturer.
I tried searching online to find out which brand the faucet might be (as there is nothing written on the faucet), but could not find the exact model (though found similar models) on kohler, delta, moen , Price Pfister.

Any ideas on next steps.
Any guess on the brand based on the attached picture.
Any suggestions on how to open the nut.