ZPDI Zero Plus Dialing I made a local collect call a 4 minute call I recieve my phone bill and this zpdi is charging me $19.31 and then another company by sharenet communications is charging me a fee for $3.29 Internet

I made a local collect call from an outside Paphone. Today I recieve a charge for $19.31 from a company called ZPDI they are charging me long distant charges, also I am being charged a fee from Sharenet communications co for $3.29. I called ZPDI they said they were informed by sharenet comm to bill me. I refused to pay I told them I was going to contact my local BBB and attorney general, they said they could credit me $4.00 only thats a lot of laughs I only been charged less than a dollar in my life for a local collect call, this is a scam I am not going to pay it I refuse too....I live in Phoenix AZ