Snovst is correct. Triumph changed the filter design but the two are interchangeable. As for the oil, Triumph allows some leeway in the owners manual. The factory Mobil is 15-50 but fully synthetic 10-40 is also allowable and and some will say that they seem to shift better with the lighter weight oil.
The problem probably is not in the merchandise but in the people skill of the folks behind the counter. This should have been explained when you bought the items.
