Go to the doctor. Seven days is too many. She might need a procedure to remove the blockage.
Try to back off form any talk about it, sometime it causes anxiety which feeds on itself, let her be in control of when she goes, sometimes all the attention makes it worse .
at this stage she is probably afraid to go incase it hurts, my daughter use to be the exact same at that age but grew out of it, the softners should start to help and force her to go but if she doesn't and remins this way maybe a blockage should be considered