Simswop issue

The sevice ismart is beyond pathetic. Having a cellphone contract with them and been trying to do a simswop for more than two months now to no avail. Been calling them numerous times using all my airtime but nothing was done yet. All i get is empty promises. The swop is not done therefore we dnt get our top up package. . While the contract ia being paid religiously monthly. Im at my witts end and dnt know where to go for help.