Hi,
Sorry for your troubles.
Could you please try setting APN not Manual or Auto, but to Custom and write the APN that your operator provided you with.
Also, please check mobile settings if there's nothing that you're forcing that your modem can't do (like connect to not existent band frequency).
If nothing helps, maybe try resetting your router as there might be a configuration involved that got your router to stop connecting, but as we don't know what has been done - reset should set everything back to default again.
EB.