Huge overcharge for services

I posted a large parcel from Bloemfontein to Cape Town via Mi Office branch at the Showgate Centre in Bloemfontein. Have used the Post Net agency on numerous occasions before it changed hands to Mi Office and was always satisfied with their charges and service. The charge for the box by Mi Office was R1113.00. I was alarmed at the cost but the parcel was urgent so I used the service. Mi Office use UTI for their carriage. On the following work day I phoned UTI to check their charges to discover I would have only paid them R678.00. Post Net in the Cape confirmed their charges would have been R617.00. I phoned the responsible Mi Office branch to query the amount and was informed that the tariff was what they charged. I feel this is absolutely exhorbitant as it was ordinary mail and not express. The parcel contained craft work from a rural project and as the client will not accept these charges the project has to subsidise a large portion of the costs. Gillian Vermaak