This answer applies to R2 Mk3
Depending on usage, it may be that the coin cell battery in the remote is coming to the end of its useable life and needs replacing. The battery type is CL2025 and these are available from many retail outlets.
Secondly, if you are using your R2 near artificial lighting (particularly low energy types), then please try turning these off and check the remote function again. From experience we’ve found that some low energy lights emit interference which affects the control system resulting in unresponsive or erratic behaviour.
If not, please do not hesitate to contact us directly on +44 (0)1702 601410 or by using the enquiry form on our contact page.