Mediacom charging me $300,00 for equipment they said I need to return but I never recieved it in the first place, And they have no record of me signing for it. Carol Stream , Nationwide,

i have been with mediacom for 21 years have always had problems after having problems for 4 months straight and nothing getting done i canceled the service. They sent me 5 labels to send all my equipment back which I did. it was recieved and signed june 9th 12:03 by hawker at mediacom warehouse. now they say i owe  them 3 adaptors at $100.00 a piece. well after calling mediacom 7 times about this one guy finially researched it and found out that they do not have a signuature from me that i ever recieved the 3 adaptors. NO KIDDING i can't return something i never got. well they stil are charging me for them and it will soon go to collections. i have tried and tried and tried to get this cleared up and all mediacom customer service and managers say is they will get back to me and they never do i just keep getting billed.