SPA-2102 I can hear them, they can't hear me.

SOURCE: LinkSys SPA 2102

try this out
power on your linksys
then pick up the phone connected to that linksys
no dile tone required
dial ****
when it says configuration menu
type 73738#
if ask for password then nothing can help you buddy
and if it says press 1 to save then press 1 and your device is reset with factory default

SOURCE: Connecting Linksys wrtu54g wireless router with Linksys SPA 2102

If you want to receive "incoming" telephone-calls:

ADSL modem <---> Linksys SPA <---> wrtu54g <---> wired computer

and Linksys SPA <--- telephone-line-1 --> telephone hand-set
and Linksys SPA <--- telephone-line-2 --> FAX machine

or Linksys SPA <-- telephone-line-1 --> mechanical telephone-splitter
with telephone-splitter --> hand-set
with telephone-splitter --> FAX

SOURCE: I just bought a SPA-2102 NA, is it possible for a

Yes - if you set provision enable to "yes" or resync from SIP to yes, they can then set your SPA to download a configuration file with an admin password you don't know.
Seems pretty rude (as in legally actionable) if they have actually done this.

SOURCE: hi I Have A Linksys

The User Name field should be left blank and the password is admin.

SOURCE: I need to hard rest

dial **** and 73738# and press 1 to confirm the resetting. wait for 1 minute
Whats the provider, sometimes they are provide locked :(