When dealing with any of the major players in the R/C parts and hobby industry if I can't pick up a phone and call them during business hours and speak to someone with a pulse I would have to think really hard before I do business with them. Thats just me, I'm not assuming Nexus does not man their phones but one post did state they prefer email communications and the original poster did say he kept getting voice mail. Plus I noticed on their site they mention a 24 hour response for emails.
I'm not saying anything negative about Nexus particularly but there are people that run online hobby shops out of their garage or on the side and typically do not have the best customer service because of the additional workload of hobby business + day job + life. I have had my race weekend ruined plenty of times trying to get parts last minute from shops that are a side business or that can't or don't invest allot into their customer service.