I have a blockchain.com account with small balance for testing purposes and tried to import using all possible options and concluded that they still don't support Native and P2SH SegWit addresses.
If you want to trade, use an exchange/instant exchange and send the funds, not import; importing your private key will only include that key pair to the wallet.
For example, importing it to Blockchain wallet wont make it available for trade right away, you'll have to send it to your "Trading wallet" first through an on-chain transaction.
Anyhow, the answer is: You can spend its funds since your private key derived that address. But a "collision" like that has astronomically low chance of happening.
Need some technical reference? read this stackexchange post: Can two private keys generate the same Bitcoin address?