I have the same problem. SONY refused to fix my MDR-1000x for free under warranty. SONY Japan service at Akihabara asked for 160 USD for the repair. My sources at SONY informed me that the reason for they charge high price for the repair is that their repairmen are neither qualified nor have the parts to replace the broken hinge (two cheap tiny plastic parts like Lego elements which came screwed and glued together) therefore they change the whole headband unit which needs the disassembly of the earpieces too. Or might just replace it to a factory-refurbished used headphone.
SONY’s corporate arrogance is soaring high and they will refuse making it right until this issue get published worldwide and start damaging their business. Therefore the only thing we can do to change their attitude is speaking up loud.