How were the Corinthians to hear from Paul until he could visit them again?

Until Paul could visit them again physically, the Corinthians were to be satisfied with hearing from him only by way of his letters. He still wanted to come and see them, but in the meantime his written letters were the means by which they would hear from him.

Les explains that Paul still wanted to come and see the Corinthians and stop in there again physically. Until he arrived, however, they were going to have to be satisfied with hearing from him only by way of his letters. The context also shows Paul wanted the giving done before he got there, so they would not give under his personal influence. His letters therefore carried his instruction in his absence.

1 Corinthians 16:5

Now I will come unto you, when I shall pass through Macedonia: for I do pass through Macedonia.

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Did Paul still want to visit the Corinthians?

Yes, Paul still wanted to visit the Corinthians. According to the context, he desired to come and see them and to stop in there again physically. Until he could arrive, they would have to be satisfied with hearing from him only by way of his letters.