I started a new job and a friend referred me for the job. The work offer a £300 bonus for bringing in new staff. My friend left the job himself a few weeks after I started whilst I was as still in my probation period. Work are refusing to pay my friend the bonus because he left before my probation period ended and have even tried denying remembering my friend referring me. It feels like they are just trying to wriggle out of paying it. I asked for the terms and conditions but they just told me the reasons I've just mentioned. Is this right?