If you still have the chipped piece of the benchtop you could attempt to glue it back on. You could use an epoxy paste as a filler but if it's mixed too dark it will make the damage even more noticeable. If you can identify your benchtop, I suggest calling the benchtop manufacturer just in case their repair quote is better value.
One way to identify your benchtop is by looking beneath it. I suggest getting a torch and looking underneath for a tag or printed name. Ceasarstone often has a large digital printout tagged onto the back of the stone top itself. This is to allow them to identify the stone top you have and how old it is. Other tops will have more or less the same style but sometimes much smaller, so keep an eye out for the printout. - EricL
We had some chips on our white Ceasarstone and we asked our stonemason to do the repairs. Since we had white he just mixed up the adhesive, filled in the chip, waited about 30 minutes then sanded it down. For D.I.Y. using a matched colour epoxy is also a good idea. - Nham