SFP Products Show Longer To Ship than Non Prime Offerings

We started on SFP two weeks ago using Royal Mail. The coverage for Royal Mail next day tracked 24 getting there on time is 43% compared to Evri and Amazon shipping showing 85%. Therefore our listings are saying order Saturday, delivery Tuesday when actually delivery is SUnday.

Our sales have now fallen off a cliff meaning that SFP isnt working, anybody got any suggestions or ideas how to make this work so SFP displays the prime badge and delivers next day?

Thanks Nataliie