[otrs] Otrs problems

Hello, A while ago in our company we have started using OTRS as main support system. Structure is as follows: customer sends an email to account A, from there it is forwarded to account B, where OTRS is downloading it. Unfortunately lately we have encountered that on OTRS no all mails were visible (comparing to mails on account A). Those missing mails don't have any special characters which might have caused any problems to the system. Have any one met such a problem ? If yes, is there any workaround ? Additional question: how to overcome the problem with emails grater than 6 MB. I would really appreciate any ideas. Cheers Gawliczek Pawel