ISA Maturity options

Hello I've requested my new ISA Provider to transfer my Cash ISA with my current provider which is due to mature on 6th April. My current provider advised in the maturity letter that if they didn't receive any instruction the balance would transfer into a low savings account and lose ISA tax protection. What if this happens before the 15 days it takes to complete ISA transfer. Will I still keep the tax free protection on any interest earned?

Hi,

The interest earned will still fall under the ISA rules.

Thank you.