Subscription payment missing

Description

A customer signing up for a subscription contacted me to say they’d received an error when they’d first logged on and then when they tried again saw that they’d subscribed twice. I checked my emails. I have two, each saying that £20 has been paid and a further 2, each confirming a subscription. I also have 2 completed subscriptions showing £20 on my database. When I logged into PayPal to do a refund for one of them, the summary page was showing as 0. Can you help?