Buy To Let Debt

A few years ago I bought a property with another investor, via a mortgage.
Recently a long standing tenant left and I stated to the other investor I now wished to put the property on the market, which was all in accordance with our original written agreement. However, I get the impression the other investor is not too happy, as he will no longer take my calls, nor reply to correspondence and is not making any contribution to the ongoing costs (mortgage, utilities, council tax, insurance etc).
Am I correct in assuming these are business debts and hence the Late Payment of Commercial Debt (interest) Act is applicable?
Thanks
Andrew

Hi Andrew
I'm not entirely sure that the situation you now find yourself in is a commercial debt in the sense implied by the act. I would advise you seek legal advice as there appears to be far more happening here than simply interest.