I'm on the £25pm always on plan and I've just had a txt saying ive had my data slowed down as ive used my 9gb of full speed ??? I thought it was 20gb fast speed
Ignore the wording of the text. It's either arrived because you've used 20GB or has been sent in error.
To check your remaining data, dial 43430, option 2 or look online: https://giffgaff.com/dashboard