Refusing To Pay Directory Services

Please note that Fortune Limited has been signed up on the 15th of June 2017 which was invoiced for the work we have done and provided to this specific company the invoice was a 30 Day invoice unfortunately when ever our accounts department contact the company regarding payment they either cut the call or ignore our calls we have made many attempts to resolve the matter but unfortunately the company is coming up with millions of excuses we have even sent the proof of the work been done we even went the extra mile to screen shot our work step by step to show the client unfortunately we have no joy, we also suggested a payment plan which fell on deaf ears, the managerial director called my company unprofessional and suspicious ,we sent our invoice advert signed contract by him art work and direct links to his advert which at the moment is displayed on the net this is simple its not hard to follow simple ethics hence the reason we have sort the legal route to recovery our outstanding debt i don't see how this is suspicious when the work which was authorized by him self the work was produced and shown as proof to him self and 2 other members of that specific company. i feel the companies should do honest business and stop making excuses when it comes to payment.