Instability of the Poolsquad 55 probe: Guide to identify the correct reference and find an online supplier.

Client
Good evening, I have a Poolsquad 55 Pumping Process with salt + pH. The probe has the reference Nov 2011 84379. The probe is unstable, it indicates between 6.9 and 8.1 and triggers the peristaltic pump at 7.6; the regulation is set at 7.2.
I recalibrated it with the recommended solutions 4 and 10. After reassembly, the probe is still acting up; I conclude that the probe is faulty. Therefore, I would like to replace it. Can you please provide me with the correct reference and the name of an "online" supplier where I can purchase one, unless you can provide it to me.
Thank you very much.
Sorry, my last question is irrelevant since you are a reseller!

Technical Advisor
Response from the technical advisor...