The only way to really fix it is to take the fondant off and fix it inside the layers. Or. Take the fondant off, press your cakes down really well to squeeze the excess out, then re smoothe the icing. Or. Take the fondant off, resmooth the icing best you can and if you can ganache it I would do that then chill it then re fondant. The ganache can hold the icing in better. The bulge is caused by different things. Too much filing without a stiff buttercream dam piped around it. Too much buttercream between the layers. Not enough around the outside of the cake to cover the separation between the layers. You also might be having air escaping and bulging the fondant. Without knowing what is inside the cakes or what it looks like its difficult to say. If you can’t remove the fondant then the only thing you can really do is use your fondant smoother to press it all back as even as possible and chill it. When the cake is delivered and comes to room temp again the bulges may come back though.