Since waiting for Call back

I am a customer and I have been loyal to them but the service I get when I need them most is poor, I have been sending WhatsApp messages, emails, messenger even calling and they will tell me all their call center agent are busy they will get back to me till today I am still waiting for their call, shem the service that you are giving me as a customer is poor very poor I am so disappointed, I trusted them as they handled my matter last year nicely but now what went wrong I don't know