There is some information on the Telkom Internet website about port prioritisation. My understanding, which maay be wrong, is that port prioritisation is purely related to bandwidth allocation in the general ADSL bandwidth pool to different ports. Some ports are completely blocked (e.g. gaming) - this is according to a product manager from Telkom.
On a general note regarding the complaint. It will be well worth looking at the S53 complaint, which was filed by ISPA, regarding ADSL. This may give some pointers. You should be able to get this from the ICASA library.
Regarding the pricing of Telkom's ADSL service, they are half right about the pricing of international bandwidth. What you need to investigate is how an international circuit, say between Johannesburg and London, is priced (on SAT-3). This will give you an idea of the costing to which ISPs other than Telkom are subject, since Telkom internet does not really pay for its bandwidth.
To understand a bit better how bandwidth in SAT-3 is priced, take a look at the following page:
http://www.ee.co.za/VectorForum/~forum.asp?action=view&primaryKey=421
Note also this quote from the above:
Edwin Thompson, UUNET:
We believe that the prices currently charged by Telkom, who has exclusive landing rights, are inflated and do not compare to the foreign half circuit costs for the equivalent capacity
Essentially, what is being outlined here is that Telkom charges much more (a multiple) for the SA half circuit, compared to what the overseas telco (like AT&T or BT) is charging for the remote half-circuit, in the self same cable.
Based on the current pricing regime, which Telkom is offering for ADSL Internet access, some major ISPs found, last year, that it would be impossible for them to offer, at the same quality of service, a service, which could compete with Telkom's on price, without losing lots of money.
What needs to be understood, if we compare the cost of ADSL Internet access in SA to a similar service overseas, is that given Telkom's leased line tariffs, an ISP cannot deliver a service at a comparable price to an overseas service. ISPs, when they build a network, are reliant on Telkom's Diginet/Martis services to provision circuits to carry traffic. The tariffing of these services is such that an Internet access service cannot be delivered at a similar price to a service provided overseas. Put simply, Telkom's Martis/Diginet and IPLS tariffs are not cost-related.
If and when other ISPs offer a service to compete with Telkom's current service, it will probably be subject to similar capping and port prioritisation, as ISPs would just not be able to afford the bandwidth to feed users.
Everyone needs to understand that the only way to address this issue is to ensure that the pricing of the underlying facilities, purchased by ISPs must be reduced.
One other point, which needs to be remembered, regarding the pricing of ADSL Internet access is that Internet Access is a VANs service, and not a PSTS service. Thus, pricing is not subject to tariffs.
Regarding ICASA - remember that ICASA is not staffed by technical experts. Bear with them, and help them. They are trying their best, but often need some help.