@ilove82 It's one sim per account so you cannot add another sim to your account, it needs to have a different username,
the personal details/address/payment details can all be the same ..... even the password if you wish, but do create another account for your other sim.
so, if I’ve managed to activate a sim not connected to my giff gaff account how do I proceed? I try to make a new account it says email already has an account, I try to add sim to account it says SIM card already activated..... help!
It's not completely clear what you have done, but you need to remember each giffgaff SIM must have its own account. When you have two + accounts each must have a unique user name, such as ilove82 and ilove182, but all the rest of the information, including the email address, may be the same.
So, using the SIM card that said it had been activated send a text FORGOTTEN to 43430 and you will receive a message with that SIM's email address & username. (You do not need to reset your password if asked.)
Do the same with the other SIM too and you will know where you stand.
It is impossible to activate a giffgaff SIM without it being linked to an account.
To receive accurate advice, please explain exactly what you are trying to achieve. For example, do you want to: