Expensive with poor service

I have logged numerous support tickets for an uncapped LTE account that constantly drops. The router has almost full signal, but internet is almost unusable, rebooting the rooter only solves problem for short time. The problem causes our mobile phones to switch over to mobile data and then uses up all the limited data, this causes an even bigger expense. If this continues I will have to cancel the LTE connection. The support tickets are closed every time as-if the problem is resolved, but it is not. The number linked to the LTE account ***