refund of upfront fee

Hi, I recently upgraded to an iPhone 11, changed my mind on the same day, and returned the phone as advised by your colleague to the delivery driver. I can see my account has been amended (which means you have got the phone back) and I am back on the old contract of £8 per month, however I've not received a refund of the £32 upfront fee i paid, and I've been charged for the first few days line rental (which was never used as the phone was returned unopened the day it was delivered. Please can you look into this for me. Many thanks Louise Gibson.