Ice on top of freezer and top shelf of door

Question

I have ice forming on the top of the freezer and on the top shelf of the freezer door. I purchased the freezer eight years ago and had the same problem when the freezer was installed. The repairman came out and fixed the problem but I do not remember what the problem was. The freezer has not been moved in eight years and was just recently moved for repairs. It seems that by moving the freezer it has caused the problem to return. The freezer is level. How can I fix this without calling the repairman again.