A REVIEW OF PEUGEOT ADBLUE DELETE

Considering that past diagnostics / code clearing drove 3 miles and light back again on / engine turned off straight away ad blue filler cap eliminated and tried to blow/suck by cap to view if ventilated. Cap isn't ventilated. remaining cap off and tissue in filler neck for eighty miles/no lights came on.Monthly bill of £644 . I've always had Peug