Netstar in breach of contract

On 20 September 2023 Netstar fitted a replacement system in my vehicle. On the same day a Fitment Certificate was emailed to me. However, this certificate did not reflect the system that was fitted to my vehicle. On 21 September I informed Netstar via an email to Customer Services that the certificate was not correct. I received an email from Netstar 0n 22 September, with reference CAS-***-N4S9, indicating that my query was transferred to an entity called EC3 to be resolved. A day later, on 23 September I received an email from Netstar Marketing Department that indicated that my ticket *** was marked as resolved. However, I never received a correct Fitment Certificate, nor was a correct certificate placed on the Netstar website at Mynetstar. On 26 September I again contacted Netstar Customer Services to inform them that Netstar deemed my query to be resolved, when in fact it was not. This time I received a reference CAS-***-Z1Z0 from Netstar via email, indicating that my query was sent to some other company. A day later, on 27 September I received an email from Netstar Marketing Department that indicated that my ticket *** was marked as resolved. However, I never received a correct Fitment Certificate, nor was a correct certificate placed on the Netstar website at Mynetstar. On 28 September I again contacted Netstar Customer Services to inform them that Netstar deemed my query to be resolved, when in fact it was not. Despite the fact that Outlook indicates that Netstar has read my email, up to today I received no feedback, nor did I receive a correct Fitment Certificate. It is clear that Netstar is incapable to supply me with a valid Fitment Certificate. I thus have no Fitment Certificate to hand to my insurance company. I am also doubtful that the system fitted to my vehicle actually works, as no information is showing on the Behaviour field on the Netstar app. I regard Netstar as in breach of contract and request that all Netstar equipment be removed from my vehicle.