Returning upgrade - what happens to sim

[BusyBee1901]

I'm returning my upgrade under the change of mind policy. I've just received the bag for it to send it away (shop closed due to covid). What happens to my sim in the meantime. I know I don't need to send it away. It is currently in my old handset under my new airtime contract. The sim will stop working once O2 have received my returned handset and I will be left without a working sim until my new one arrives with replacement handset?? Help. I've been told over the phone that I can't order an exchange now, need to wait until they have my handset. I had thought I could order a new one with O2 over the phone at the time and the courier bringing my new phone would take away my returned item. Obviously not. Please help, can't be without a sim for a couple of days.

[MI5 · Accepted solution]

@BusyBee1901 

Your sim will continue to work.

O2 will update it over the air so it will revert back to your previous tariff automatically.