I paid voluntary class 3 payments from the netherlands via bank transfer

So after a year or more of trying to figure out what to do, today I received a letter confirming I am eligble to pay Class 3 contributions, I live abroad right now and wanted to pay for the years 2006-2007 and 2012-2013, as these are years I worked in the UK but evidently missed a few weeks so did not qualify for the full year. After talking to a nice guy via the website chat, he told me to simply transfer what I wanted to pay with the bank details So I did this. How will they know what I am paying for? As in, which years? I feel like i've just blindly sent money to a UK account with no instruction as to which years I am paying for, since I am not paying ALL of the missing years. When do I get a receipt or an acknowledgement that they received the money? Does anyone know how long it takes for my records to update so that I can see my pension forecast after completing the payement?

Hi RebeccaB1984 Bee,
It can take up to 8 weeks for your payment of voluntary contributions to be reflected on your National Insurance account.
Once your payment has been allocated to your account it will then appear on your Personal Tax Account and you will be able to check your revised pension entitlement.
When we receive a payment by bank transfer we do our best to determine where it should be allocated to but if you don’t agree with the action that we’ve taken please let us know and we’ll amend it for you.
You may wish to call our National Insurance Helpline on 0300 2003500 (from the UK) or +44 191 2037010 (from overseas) to advise how you would like your payment to be allocted.
Thank you.