If Blockchaindotcom follows the Bitcoin standard of BIP32, then the 12 words should allow you to recover your funds on any wallet. You can try downloading Bluewallet and recovering the wallet there.
You do not need to "import addresses" to access your funds, as long as you have your private keys (which are derived from the 12 words).
If you have a custodial account with Exchange.blockchain.com, you must contact them for help. They own the money, not you ("Not your keys -- not your bitcoin").
If you have a non-custodial wallet downloaded from Blockchain.com, you should normally recover control over your money by restoring the wallet from a backup or from a safely stored record ...