Roaming add-ons

Roaming add-ons are available from Lebara, but the maximum available (for South Africa) is for £15 for 3GB for 15 days... This hardly seems adequate and even though and could become quite expensive very quickly as 3GB might not be enough and doesn't offer any reassurance with such a small amount of data, even with pretty good free WiFi accessibility... I want to use Lebara and in essence, keep it in-house, but other companies offer more for less. Why can Lebara not do the same, or better still; offer this as a 'buy in' and I then have access to my 'normal' data in addition?

If your phone supports esim there are alternatives.
Travellers usually check out EsimDB.

Thanks for the assist, although I was hoping Lebara would consider this as a moving forward thing