ESA Medical appeals procedure

My husband has been contacted by DWP to say that he has failed his medical assessment for continuing ESA payments. My concern is that he was informed of this over the telephone. He told the person on the phone that he had a current medical certificate of unfit to work. The contactor said that he would send an appeal form through the post. A leaflet called "If you think our decision is wrong" arrived by post this morning, with no covering letter whatsoever. Surely he should have been informed of their decision to fail him of his test in a letter? How can he fill in the section of the form to say WHY he disagrees with this decision if he was not given notification of his reason for disagreeing?

Thank you, Gordon. I have drafted and sent by recorded post a letter requesting a copy of the medical assessment. We would phone the DWP to request this by phone, but we don't have and can't seem to obtain a phone number to do this.

No security checks were used when the DWP phoned my husband. It could have been anyone they were speaking to, including any male relatives who don't know about his ESA benefits.

Regards

Dianne