Akon -- Contractor's Ripping Me Off Because I'm Famous

Akon has no plans to pay a $51,000 construction bill on his Georgia mansion -- insisting the man behind the 5-figure tab not only butchered his home ... he actually tried to EXTORT Akon to get the cash.

Akon just filed a countersuit against a guy named Jay Poorak -- who runs a company called Southern Electric -- insisting Poorak performed construction work on Akon's house without ever hashing out an agreement about the services or price.

According to the lawsuit, Poorak attempted all kinds of construction on Akon's home -- including electrical work, framing, and cornice work -- without any permission ... and the work was a disaster.

But that's not it -- Akon claims Poorak completely ripped him off ... charging him over $150,000 for the job ... when it was only worth $33,660.

Akon claims he already paid Poorak $44,650 -- despite the hack job -- and now wants at least $10,990 back ... the amount Akon believes he overpaid.

Akon claims Poorak threatened him over the balance in question with legal action and "the besmirching of [his] reputation" if Akon didn't pay up.