It is probably worth a try to fix it yourself, if you don't mind a little work and perhaps buying a new gasket. Often it is enough to open up the securing clamp, remove the top, clean and inspect all surfaces on the gasket, top, and bottom, lube the gasket with a silicone based plumbers lube, and then put everything back together again. If you find any nicks, cracks, or tears in the gasket you will need to replace the gasket. If you find a chip in the surfaces on the top or bottom that press against the gasket you have a larger repair, which might warrant calling a service person depending on how much you want to take on.