Thank you both for your replies. I am just nervous because my house does not have a doorbell and scared I might have missed the knock. We had one mail by Royal Mail yesterday for my housemate, and today our nextdoor neighbors received a mail from Royal Mail (I know this because I rushed to the door when I saw the RM person hoping it was for me but it was not). So all these, overthinking, and being new in the country made me excited and nervous, plus no reply from help chat. However, thank you all again!
About phones, I am yet to figure out the procedure here but I am thinking of buying some no sim contract or monthly prepaid contract and if the money gets withdrawn automatically I would like it to be from Monzo as I am planning to put all my money that is in my foreign card to Monzo (via transferwise so I will receive it as GBP). Will update here if I receive my card or if I have any questions.