Payment made but not showing on my account, advisers aren't helping...

I paid my tax last week, I made two different transactions. The first transaction went through fine, I received payment confirmation and a reference number. When making the second payment, the website crashed. Money was taken from my account but I haven't received any confirmation. When I log in to my account, there is a section which says "Payments made in the last 7 days" and it only shows the first payment made, not the second one. I've contacted HMRC about this and they've not been very helpful, has this happened to anyone else? How should I go about trying to fix this? Thanks!

Hi
If the second payment has left your account and it has been 7 days and still not showing on your account, you will need to contact us to provide details of the payment and we can send a request to trace it.
Self Assessment: general enquiries
Thankyou.