Hello Dxmstle,
Welcome to the community!
No, only a customer can request an IMEI to be blacklisted. If an account has defaulted, all costs are charged to the account. However, your services can be suspended for non-payment (see Terms of Service; section 2i). If the payments remain unpaid, the account would go into collections (see here).
Are you having issues with your device? Are you having difficulties paying? If you're having difficulties paying, you might consider contacting the credit operations team to make a payment arrangement.
Hope this helps 😀
Cheers
