Devolo extenders and new Livebox

After some very useful suggestions on this site last year, I installed a pair of Devolo Wi-Fi extenders with great success giving me coverage over all our property made up of two buildings. On the suggestion of France Telecom/Orange, I was supplied with a new black Livebox. Ever since, I have been unable to link the extenders to the new Livebox despite loads of phone calls to the Devolo helpline. Has anybody else had a similar problem when changing routers? I will replace the extenders if I have to but this is not a cheap item! Thanks in advance for any help.