My housemate shamed me saying 'ask forgiveness' when I said Wallahi, implying I lied. Later I said Wallahi in front of our other housemate and he said 'you don't have my trust to say Wallahi.' I said 'shut up, who are you that I need your trust?' Was I wrong?

Ustadh AbdulAziz al-Haqqan

This seems to me a little bit childish. The issue here is about lying. If it is about lying, then do not lie if you have actually done so. If not, then your friends are being disrespectful.