Cannot add Auto Renew Pack

[Cottage]

I purchased a Three PAYG sim from Amazon with a 40GB data pack installed.  It is due to expire on 21 January.

I am trying to add a Three auto renew 60gb pack at 10 a month to my existing phone number , but I cannot. 

Whenever I go to purchase this auto renew pack, the website asks me whether I want a Sim or Esim. I don't want either. I want to apply the pack to my existing phone number. 

I have tried to speak to someone via 333 but apparently I only get digital advice. I have tried asking via the digital assistant but keep getting into a loop. 

Please could anyone here advise? 

[PeteG]

Hello there.

It sounds like you're on the general purchase page, purchasing a new SIM with Data Pack. I new SIM shouldn't be required if you're just topping up and adding a Data Pack to your plan, something you can do once you've signed into My3. 

Pete.