It would appear that spammers have 'spoofed' your email address. Unfortunately once these people get hold of your address it is very difficult to do anything about it.
Are the returned mails to [email protected] username, if so you could probably arrange for Orange to blackhole any mail not sent to a specific mailbox for your account. The other option is to cancell that account and open another one. (That is assuming that you finally manage to contact Orange)