I had the same problem. First I tried to fix it with contact spray, but the volume doesnot work. The next thing I tried was to put in into the contact spray for a night and than I dried it at 42 degrees C in the oven. But after that I was able to loosen the tiny upper half of the touchpanel. I tried to clean it with alcohol but unfortunately I wiped the copper track away so they a partely ereased. The set is completere useless since new keypads are no longer available. 
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