Tandem Membership Application Stuck on "7-Day Wait" for Months

I applied for a Tandem membership, but every time I try to access the app, I’m told to wait 7 days for approval. Despite waiting months, I still can’t use the app. A friend of mine was approved within a single day when they signed up, so I don’t understand why my application is being delayed repeatedly. I’d like to know the reason for this extended wait and whether there’s any way to expedite the process. Please assist me in resolving this issue so I can finally access my account and start using Tandem as intended.