Can't get through

I am having continual problems getting through to the Hosmed call centre on ***. it doesn't matter what time of the day or how often we phone, the message is 'the network is congested' and the call won't connect. I have tried phoning the Head Office number from the website and it just rings through to a full mail box. I have tried a number of times in the last week. Does Hosmed perhaps have an alternative contact number? <br> Thank you