If they were the original batteries, contact the manufacturer or seller for a replacement unit. Repairing a unit with leaky batteries can be futile, you are always chasing new corrosion.
If you purchased the batteries separately, contact the battery manufacturer for a replacement of the unit. Any reputable battery maker has a warranty.
Although my response won't help your current situation, it may help in the future. Leakage is one of the many reasons to move to Ni-MH rechargeable batteries. Standard (lead-acid) batteries leak. In my personal experience, I have found Energizer batteries to be particularly susceptible to leakage, while Duracells are least likely. If a purchased device comes with a battery brand that I am not familiar with, it gets tossed in the trash immediately. I will not use standard batteries in any device where the batteries will be installed for more than six months. I have been using Ni-MH batteries for over eight years and have never had any leakage whatsoever from any of them. I recommend Eneloops, but there are quite a few brands out there.