Names mixed up on group account

Years ago I took out a Smarty plan for my son and due to his age at the time, I took it out in my name. Later on I decided to also move to Smarty and as there was an account already in my name, I used my son’s name with the intention of getting Smarty to just swap the names over. I now realise this was a mistake on my part. As my son gets older, now an adult, it makes sense to have the accounts in the right names but Smarty say this isn’t possible. Google agrees and offers a solution where you port your numbers temporarily to another provider but in the correct names then port them back to Smarty. This seems a bit extreme to get to the correct position when all Smarty need to do is swap the names over. After all, it seems I can eventually get to the correct position myself but with a lot of hassle. We can provide proof of id etc but as there not been a name change for either of us they won’t help. Seems crazy to me and they are yet to offer a reason why they won’t or can’t do it other than we just can’t. Both names are in a group account and at the same address. Maybe it’s just me and the real solution may be to port away from Smarty and leave it at that but it’s a shame. Does anyone know a better way or if Smarty read this, can you please help?