Won't supply correct and complete documentation for my bank's records

Imported items from China. UPS tried contacting me via phone and I noticed missed calls. Why do companies do that, calling when they should be emailing? What do they I will do, phone my documents through. They wanted the codes for the items which I provided via email. They then entered the wrong code and I was over taxed. For a week I would then email them the right code, they would reply here is your 'new' bill which would be exactly the same as the previous one until I eventually received a bill that was almost double the original over taxation. I wrote to SARS who wrote to UPS who finally corrected the incorrect code and I was correctly taxed. Imagine that, getting better service from the tax 'authorities' rather than a private company! They did not supply the correct documentation for my bank, and then supp**** incomplete documentation. This situation has never been resolved in a month of constant emailing.