Alternative employment

I have been told in work that there will be no redundancies but the have found alternative employment within the company, the hours are completely different and the job will now entail been in a call centre role on phone line all day were as before I was answered phone line 10% of the time , do I have to except this role or can I refuse, they have offered a four week trial in the new position , but I don’t want to except the trial if it commits me to something that is not acceptable as alternative employment

Doing a trial period will not commit you to anything - a trial period is just as it sounds, a chance for you to see whether the alternative job is suitable. If you find it is not, you can then say so and, assuming you are reasonable to do so, should still be able to claim your redundancy.