Postage labels

Hi All,

 

I listed 4 jackets each were listed with postage via the simple delivery label system buyer pays with EVRI as the courier. A lady has bought all four and would like combined postage but does not want EVRI rather Royal mail. The weight of all four exceeds the weight limit of the delievery label for one.

 

How do I:

 

1. Change the courier?

2. Refund the buyer the difference in postage without losing money myself?

 

Is there any way of cancelling the delivery labels and starting again or booking them into Royal Mail myself??

 

Thanks for your help.