Sub tank problem

Hi all,
We have a 97 model 4.5Lt St Gu,,,, Recently we had to have the fuel pump replaced to a (Generic), but they forgot the filter on the first run, then we went back to have the filter replaced, then the sub tank wouldnt work, ( which it did just fine before they " fixed" everything) and they want more money telling us that it is a sender unit -- a further $440, - genuine as there are no generics...... could we be lucky enough that it may be a wire issue-- or would it be our misfortune that they shorted it out with the change over??? the fuses are ok, no burn outs there....
OH, also, we were told when we bought her that the engine started out of the sub tank-- which now cant seem to be true as we have no issues starting and running her for the last 3 weeks with the sub tank being " broken" ???

Patrols always drawer out of the main tank, the sub tank pumps into the main. At every start the sub tank module automatically switches on the transfer pump for a short period to keep the fuel turning over.

Check this thread for info on sub tank issues; http://www.nissanpatrol.com.au/forum...k-light-issues

tony