Refunds using a third party gateway

[Ben1973]

Hi there - I use Opayo/Sagepay as my payment gateway (I am based in the UK) as their rates are far more competitive than Shopify Payments. However, the only issue I have is that if I have to refund someone Shopify will not put the correct amount in on the refund amount (they just leave it as zero) so I therefore I cannot send my customer the automated confirmation as they think I am not returning the money owed to them. Can anyone help in overcoming this issue? Many thanks