Sorry you've also had the troublesome farce.
Thank you for the Money Helper link. I also had a ridiculous time trying to pay some NI years to increase my SP amount in 2023. I had to hold on forever for Future Pensions, then decide which years to buy, then phone someone else to get the bank details and reference for my payment. Absolutely no acknowledgement for receipt, it's really not good enough when you are transferring large sums.
Three months later my forecast still hadn't been updated so I held on the phone for another forty minutes and finally got through. 48 hours later it was updated.