A person who has paid a rate of interest for the loan or use of money at a rate in excess of that provided for by this act or otherwise by law or has paid charges prohibited or in excess of those allowed by this act or otherwise by law may recover triple the amount of such excess interest or charges in a suit at law against the person who has collected such excess interest or charges: Provided, That no action to recover such excess shall be sustained in any court of this Commonwealth unless the same shall have been commenced within four years from and after the time of such payment. Recovery of triple the amount of such excess interest or charges, but not the actual amount of such excess interest or charges, shall be limited to a four-year period of the contract.