System disk deleted space

I HAD a 1TB USB disk, partitioned into 2 x 500Gb - NTFS. Both partitions had data. I created a system restore disk on what I thought was one partition, but the result was that I ended up with one FAT 32 32Gb partition (called Restore), with approx. 27Gb spare capacity. All the other data was wiped. I can only re-format the disk as NTFS, losing the Restore volume - which is really no problem so I have done this. I don't seem to be able to erase the volume and start again on a 1Tb volume. Is this possible? And I assume the previous data is lost forever, on both partitions? Where are the other Gbs?
Thanks,
Mike

Bastet said:

I would try recuva to see if it’ll find any files.
https://www.ccleaner.com/recuva/download

To get back to a 1Tb drive:
You can use diskpart to clean the hard drive.
open powershell with admin & enter
diskpart
list disk
select disk X (where X is the number of the external hard drive
clean
exit

Once you open disk management it’ll ask you to initialise the disk.

Thanks, I've already tried this and it only finds the new system recovery. I'll work on your suggestion below.

spunk said:

The Default behavior when you create a System Restore disk is to wipe the drive and format it and add the recovery files.
Since the partition has been overwritten, you probably won't find any data. But I have had luck with GetDataBack. it is free to download and to scan, if it doesn't find anything, you don't have to pay, just if you want to restore your files to a different drive.which is the same size or larger. To gain full capacity, you can use Diskpart as sated or go to Disk Management and delete each partition so that it is all Unallocated Space, then right click the Unallocated Space and create a New Simple Volume, Format it NTFS

Thanks. I've tried the 2 undelete suggestions but the previous data has gone. I've now formatted the drive and regained the 1TB space. However, when I plug another USB drive in, I lose Wi-Fi connectivity!