Try this give the RSPCA number a ring
Tell the operators that you left your dog in the care of a trusted organisation
When you went to see the family pet it was shown to you
Dead,skinned and in a plastic bag
What should I do
The operator will say oh my god that's unbelievable I need to take some details who had the dog
Then you will be passed on to ten other departments
Then told to its an offence to make crank calls
Give it ago I have three times