Jai Srimannarayana!
In Tamil there are no many a letter. They have to be adjusted for somany other sounds. Hence there will be some problem in fixing up the usage of particular sound to a particular letter. ‘ka’ may be pronounced as ‘kha’ , ‘ga’ and ‘gha’ also. You need to choose your own sound from that letter. So also here with the word Venkata. If you take this word as a Tamil word you can pronounce either ‘vekata’ or ‘vengada’ makes no difference. If you take the word as a sanskrit word then it should be ‘ve:nkata’ only.

For Tamil one, the meaning was already given by Nammalwar as, ‘kadangal ve:m’ kadangal=unavoidable debts like karmas, which soul carries along with it, which should be otherwise experienced without any hesitation, will be, ve:m=burnt to ashes, when one surrenders unto Him.

In sanskrit the meaning was given in a different way like ‘ve:m’ = all the links with one’s own sins, ‘kata=will be cut off in total, to one, who surrenders to Him.