How to Purchase a Second Purchased Retainer

Earlier today I successfully a third retainer. But I would like a fourth asap simply because it is a bit easier to level them both up at the same time.

When I go to the mog station to order one additional paid retainer I am unable to complete the process. If I click on the "Next" icon on the bottom right of my screen I just get sent back to "Retainer Services" page.

If I try instead to click on the "Manage Retainer Service" icon and the click on the "Next" icon on the bottom right of my screen I am sent to a page with an ERROR message in the upper left hand corner and the following statement "The Payment Method for your Current Service Subscription will not be Charged".

Additionally I went to my Steam account to see if there was an option to purchase an additional retainer, but could not find one.

If anyone has had this same problem and overcome it, please let me know how you did it. I did file a support claim with SE, but am impatient to get started with both new retainers at the same time.

Thank you for your help.

*Earlier today I successfully PURCHASED a third

It's because you already have one additional retainer. It's asking how many retainers you want in total. So you need to select "Two additional retainers" (in total) and then it'll proceed to charge you for the extra one.