Your case is different from others who purchase on blockchain.com if you really mean it disappeared.
Others just can't move their funds due 7-day rule from trading wallet to main wallet of blockchain.com, see their terms
When you place purchase orders in the Trading Wallet, we may impose minimum holding periods in respect of any Virtual Currency that you have purchased which may last up to a maximum of 7 days. These minimum holding periods are necessary to enable us to carry out effective fraud prevention measures and to ensure that the fiat currency leg of any given transaction has settled. After this minimum holding period elapses, you may trade your Virtual Currency in the ordinary way.
This is reasonable if they accept credit cards.
An unfortunately, blockchain.com has very poor customer support, you may end up hanging your email even you follow up everyday. But just try than doing nothing.