TTRS Won’t start

Hi hoping for some guidance here filled up on motorway yesterday with super unleaded as alway and then 2 miles down road total loss off power pulled over and will not restart just cranked over Fuel gauge showed empty and did have warning of
“tank system malfunction report to workshop”
On checking engine bay notice the oil filler cap had also vibrated loose and oil spray in bonnets not a lot still plenty in sump
Transported back home and still no signs of it firing or showing fuel on gauge had an ear to both pumps and they seam to be purging
Lost for next item to check now don’t know if contamination in fuel or pump module or HPFP just stumped
CRB

Hi there it’s the Mk2 8J model the oil was still well up the dip My engineer has located a dead relay so far but Audi haven’t got one in stock and then he’ll move in to why the duel gauge and trip both read zero so fingers crossed it one of them wired gremlins you get now and then