Charged $69 by mistake because of a bug in Travis

Hi support team,

I had a project on cloud project on Udacity scholarship that requires us to use Travis CI in order to setup a pipeline. so I signed up on Travis with my Github account, and chose free plan to only do the project which gave me 10000 points as credit. But I faced a weird error from Travis that “you exceeded the number of users allowed for your plan. please switch to a bigger plan new user”, Although I was freshly registered.
I was on a hard deadline so there was no time to wait for the support team to fix this, so I had to purchase the cheapest plan in order to continue my project. So I need to refund the amount that deducted from my credit card and cancel my subscription please.