Relaxo Footwear — foot developed dark marks which doesn't go. skin discoloration

I purchase a Sparx footwear on September 2017 and from March beginning onwards I noticed that the footwear was giving out foul smell and I had to wash it every week .Around the end of first week of March I observed discoloration and under my feet it looks like a big brownish red mark. This is the first time am facing such dreaded issue after wearing a footwear. This is such a pathetic experience I am scared as in what is that mark under my feet till date it has not gone and the mark remains. I will go for a skin check up and will file this under consumer forum. How can you sell such degraded products to your customers? I believed in Sparx and I never had an issue with any other brands. Sparx has really let me down. Am really afraid of the skin discoloration that am having right now on my feet. You'll have used degraded cheap rubber that causes this.
I have wasted my time and money behind your product. This is really unacceptable. I thought that the mark will go away but it has been around 30 days now and it is not going at all. Worst of the worst.