I believe they're currently owned by Alcatel-Lucent.
»en.wikipedia.org/wiki/Al ··· l-Lucent
Alcatel-Lucent acquired Nortel's UMTS radio access business at the end of 2006. During 2007 the company acquired Canadian metro WDM networking supplier Tropic Networks, Inc.; enterprise services gateway products developer NetDevices; IPTV software company Tamblin; and the telecommunications consulting practice Thompson Advisory Group, Inc.
I'd suggest contacting Alcatel's headquarters in France for info on an RMA.