Do not be scared if you will notice that your bitcoin address is changing all the time, it's their normal practice and everything is working fine.
Blockchain is being really preferred by the millions of users across the globe due to its security feature and the quick transfer during the non rise period. But when the price starts the bull run their unconfirmed transaction gets a long queue and also their fees goes like crazy and my friends have even paid 30 - 50 $ to transfer from one wallet to another.
By default it will have the moderate fee to make the transaction. If you guys do modification on the settings then you will be find the transaction delay and it will be queue for long time mate. Then personally I do not have the blockchain for continuous transaction.
For simple holding this blockchain wallet has been widely used mate. Then fees are really trouble when the mempool has been filled more.
That 30 USD transaction and all not a possible fees now. You may pay 1 USD as a fee for the transaction now bro.